Abstract：
:Knowledge of oocyte development and the early differentiation of the germ layers in monotremes stems largely from two articles by J. P. Hill and T. Thomson Flynn. The completeness of their account was due to the large series of echidna ovaries and eggs collected on Tasmania by Flynn, an Australian biologist of whom a brief account is given. A striking finding in the oocyte and early embryo of monotremes was the presence of a latebra connected to the yolk bed beneath the germinal disc as described in birds and several reptiles. A further resemblance was the presence early in vitellogenesis of a striate zone beneath the zona pellucida. Cleavage resulted first in a lens-shaped blastodisc encircled by cells called vitellocytes that later fused to form a germ-ring. The blastodisc gave rise to a blastoderm that eventually became unilaminar but comprised two cell types identified as ectoderm and primitive endoderm. Eventually these segregated into two layers and formed a blastula. This sequence resembled that in marsupials except there was no obvious distinction between future embryonic and extra-embryonic regions. As the blastoderm extended over the surface of the yolk, it was preceded by the germ-ring that eventually played a role in forming the yolk navel. This was a unique feature of monotreme development. It is shown that Flynn played an important role in analysis of the material as well as in its collection.
journal_name
J Morpholjournal_title
Journal of morphologyauthors
Carter AMdoi
10.1002/jmor.21319subject
Has Abstractpub_date
2021-01-03 00:00:00eissn
0362-2525issn
1097-4687pub_type
杂志文章abstract：:Osmotically induced alterations in the ultrastructure of the apical crypts of chloride cells and changes in chloride efflux were studied in striped bass (Morone saxatilis). Striped bass were divided into three groups: fish adapted to freshwater, fish transferred directly from freshwater to 100% seawater (3% salt, w/v)...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.1052090204
更新日期：1991-08-01 00:00:00
abstract：:Whole body studies of Plotosus tandanus revealed that ampullary pores occur over the entire body of the fish, but are in higher concentrations in the head region. These pores give rise to a short canal (50-60 microm) produced by columnar epithelial cells bound together by tight junctions and desmosomes. At the junctio...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.10063
更新日期：2003-02-01 00:00:00
abstract：:The site and process of urine formation in the renopericardial system of Helisoma have been investigated. Osmotic pressure and protein content of hemolymph from the heart, pericardial fluid from the pericardial cavity, prourine from the kidney sac, and urine from the ureter have been determined. Osmotic pressure is eq...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.1051690209
更新日期：1981-08-01 00:00:00
abstract：:The evolution of viviparity alters the physical relationship between mothers and offspring and the prevalence of viviparity among squamate reptiles presents an opportunity to uncover patterns in the evolution of placental structure. Understanding the breadth of this diversity is limited because studies of placental st...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.20912
更新日期：2019-01-01 00:00:00
abstract：:Studies of echinoid microscopic anatomy over the last two centuries have created a number of inaccuracies and mistakes that have accumulated in the descriptions of the intricate organization of the coelomic system of Echinoidea. To clarify the situation, we reconstructed the axial complex and radial complex of the ech...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.20811
更新日期：2018-06-01 00:00:00
abstract：:The lizard tail is well known for its ability to autotomize and regenerate. Physical contact of the tail by a predator may induce autotomy at the location at which the tail is grasped, and upon detachment the tail may undergo violent, rapid, and unpredictable movements that appear to be, to some degree, regulated by c...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.20269
更新日期：2014-09-01 00:00:00
abstract：:Among egg-brooding hylid frogs there is much interspecific variation in the degree of development of the young at hatching. In certain species of Gastrotheca the eggs hatch into free-living tadpoles, whereas in others (and in the genera Amphignathodon, Cryptobatrachus, Stefania and Hemiphractus) the eggs hatch directl...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.1051820102
更新日期：1984-10-01 00:00:00
abstract：:The nurse shark, Ginglymostoma cirratum, is an obligate suction feeder that preys on benthic invertebrates and fish. Its cranial morphology exhibits a suite of structural and functional modifications that facilitate this mode of prey capture. During suction-feeding, subambient pressure is generated by the ventral expa...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.10626
更新日期：2008-09-01 00:00:00
abstract：:To investigate whether the thickness of the cornea in snakes correlates with overall anatomy, habitat or daily activity pattern, we measured corneal thickness using optical coherence tomography scanning in 44 species from 14 families (214 specimens) in the collection at the Natural History Museum (Denmark). Specifical...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.21094
更新日期：2020-02-01 00:00:00
abstract：:Morphologists and systematists have long suspected that dietary consistency can affect skull and dental form in mammals. We examined plasticity of skull shape and tooth morphology in prairie deer mice (Peromyscus maniculatus bairdii) by feeding mice diets that differed in consistency but not nutritional quality. Shape...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/(SICI)1097-4687(199608)229:2<229::AID-JMOR
更新日期：1996-08-01 00:00:00
abstract：:This study examines the allometric scaling relationships of the cetacean humerus, radius, and ulna. Bone lengths and diameters were measured for 20 species of odontocete and three species of mysticete cetaceans, representing eight of the nine extant cetacean families. The scaling of individual bone proportions (bone l...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.1052220208
更新日期：1994-11-01 00:00:00
abstract：:Testicular samples were collected to describe the ultrastructure of spermiogenisis in Alligator mississipiensis (American Alligator). Spermiogenesis commences with an acrosome vesicle forming from Golgi transport vesicles. An acrosome granule forms during vesicle contact with the nucleus, and remains posterior until m...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.10872
更新日期：2010-10-01 00:00:00
abstract：:Asymmetrical monorchy, or the complete absence of one testis coupled with the presence of its bilateral counterpart, is reported for 174 species of the carabid beetle tribes Abacetini, Harpalini, and Platynini (Insecta: Coleoptera: Carabidae) based on a survey of over 820 species from throughout the family. This condi...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.10319
更新日期：2005-04-01 00:00:00
abstract：:The arrangement of the musculature and the fibers of the extracellular matrix (ECM) in the flexible jaw joint of the sandworm Alitta virens (Annelida, Polychaeta) was studied using dissection and histology. The jaws are capable of a wide range of motions principally related to defense and feeding. The left and right j...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.20349
更新日期：2015-04-01 00:00:00
abstract：:The form of amniote claws has been extensively investigated, often with inferences about ecological association being drawn from studies of their geometry. Various methods have been used to quantify differences in the geometry of claws, but rarely have the underlying assumptions of such methods been addressed. Here, w...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.20625
更新日期：2017-02-01 00:00:00
abstract：:The Eurasian lynx (Lynx lynx) is a medium-sized felid, with a tendency to hunt for prey larger than itself. We studied the lynx hindlimb musculoskeletal anatomy in order to determine possible anatomical adaptations to hunting large prey. In our previous work, we had found characters of both large and small felids in t...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.21328
更新日期：2021-01-25 00:00:00
abstract：:The omphalallantoic placenta is a complex organ that is unique to viviparous squamates. Using transmission EM and light microscopy, we examined this placenta in garter snakes in order to understand its structural organization and functional capabilities. The omphalallantoic placenta is formed from the uterine lining a...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.10084
更新日期：2003-05-01 00:00:00
abstract：:The coiled shell of gastropods begins as a cap-shaped lens of organic and calcified material that covers the posterior dorsal side of the larva. During development the cap enlarges to cover the larval visceral mass. Marginal growth then produces the characteristic coiled shell. One model of the initiation of shell coi...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/(SICI)1097-4687(199801)235:1<77::AID-JMOR6
更新日期：1998-01-01 00:00:00
abstract：:Amphisabenia is a group of squamates adapted for a fossorial lifestyle. The skull is the animal's the main digging tool, and can present one of four principal shapes. The shovel-headed shape is considered to be the most specialized for digging. The South American genus Leposternon presents a shovel-headed morphotype, ...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.20899
更新日期：2018-11-01 00:00:00
abstract：:Body length is one of the most important factors that influence organismal function and ecological niche. Although larger animals tend to have a suite of physiological advantages, such as lower mass-specific metabolic rates and lower costs of transport, they may also experience significant limitations to unsteady loco...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.20846
更新日期：2018-09-01 00:00:00
abstract：:The cellular populations present in dorsomedial cortex in the snakes Constrictor constrictor, Natrix sipendon and Thamnophis sirtalis are described at the light microscopic level using Nissl and Golgi preparations as well as at the ultrastructural level. This area plays a central role in cortical organization in snake...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.1051610207
更新日期：1979-08-01 00:00:00
abstract：:An ultrastructural study of the ovary of the sessible jellyfish, Haliclystus octoradiatus, indicates that it is fundamentally different from that of other scyphozoans and is the most structurally complex within the class. Oocytes develop within a series of spherical, sac-like ovarian follicles consisting of an enlarge...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.1052180210
更新日期：1993-11-01 00:00:00
abstract：:Sea urchin adoral tube feet are highly specialized organs that have evolved to provide efficient attachment to the substratum. They consist of a disk and a stem that together form a functional unit. Tube foot disk tenacity (adhesive force per unit area) and stem mechanical properties (e.g., stiffness) vary between spe...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.11004
更新日期：2012-01-01 00:00:00
abstract：:Cover illustration. Mayetiola destructor is a major pest of wheat in Europe, North Africa and North America. In this issue of the Journal of Morphology, Schneeberg et al. (pp. 1299-1311) investigate the adult head structures of the cecidomyiid fly and compared their findings with evolutionarily less successful familie...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.20220
更新日期：2013-11-01 00:00:00
abstract：:The location and arrangement of the pancreatic endocrine tissue in larval and adult Geotria australis (Geotriidae) differ markedly from those exhibited by the comparable stages of Northern Hemisphere lampreys (Petromyzontidae). In larval Geotria australis, the main zones of islet proliferation are located laterally be...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.1051840302
更新日期：1985-06-01 00:00:00
abstract：:Odontophoral cartilages are located in the molluscan buccal mass and support the movement of the radula during feeding. The structural diversity of odontophoral cartilages is currently known only from limited taxa, but this information is important for interpreting phylogeny and for understanding the biomechanical ope...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.10699
更新日期：2009-05-01 00:00:00
abstract：:Tooth development and replacement in fetal and adult viviparous caecilians (Amphibia: Gymnophiona) are described and analyzed according to current theories of tooth succession. The fetal dentition differs from that of the adult in morphology, position, and function. Teeth are used by fetuses to scrape the oviducal epi...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.1051480104
更新日期：1976-01-01 00:00:00
abstract：:Adult female white-footed mice, Peromyscus leucopus, were exposed to long (LP) or short (SP) photoperiods for 6 weeks (experiment I). Another group of animals was kept for 6 weeks in SP, then injected SC with 30 micrograms prolactin twice daily for 2, 3, 4, or 6 days (experiment II). Ovaries from the mice in both expe...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.1051760211
更新日期：1983-05-01 00:00:00
abstract：:Knowledge about the diversity, locomotor adaptations, and evolution of the marsupial forelimb is limited, resulting in an underrepresentation of marsupials in comparative anatomical literature on mammalian forelimb anatomy. This study investigated hand proportions in the diverse marsupial order Diprotodontia. Fifty-tw...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/jmor.10495
更新日期：2006-12-01 00:00:00
abstract：:The cuticle-lined foregut of Derocheilocaris remanei consists of the mouth with its associated labrum, and an undifferentiated esophagus. It is separated from the midgut by an esophageal valve. The labrum is a conspicuous structure moved by five pairs of muscles (four dorsoventral and one longitudinal). Four pairs of ...
journal_title：Journal of morphology
pub_type： 杂志文章
doi：10.1002/(SICI)1097-4687(199611)230:2<199::AID-JMOR
更新日期：1996-11-01 00:00:00
