Studies from the morphological laboratory in the University of Cambridge, ed. by F.M. Balfour (A. Sedgwick).Williams and Norgate, 1880 - 113 pages |
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Studies from the Morphological Laboratory in the University of Cambridge, Ed ... Morphol Lab Cambridge Univ Aucun aperçu disponible - 2016 |
Expressions et termes fréquents
adult alimentary canal Amphibia appears appendages area pellucida axial Balfour basipterygium become blastema blastoderm blastopore body cavity body-cavity chick connected considerable continuous cortical derived described dorsal Elasmobranch Elasmobranch Fishes embryo embryonic area epiblast excretory system external glomerulus fin-rays formation formed Fürbringer ganglia girdle give rise glomerulus head-kidney hypoblast Ichthyopsida inner mass intermediate cell mass invagination kidney blastema later layer limbs longitudinal lumen Malpighian body mass of cells median line medullary groove medullary plate ment mesoblast mesonephros Müllerian duct nerve neurenteric canal notochord nuclei observations organ outer ovum Pecten pelvic fin peritoneal epithelium posterior primary tubules primitive streak procephalic lobe pronephros protovertebræ rays region retina ridge rudiment seen segmental duct segmental tubes separated shows side skeleton somites structure suprarenal bodies Teleostei thickening tion tissue trace transverse section ureter vascular vertebral vesicle wall Wolffian blastema Wolffian body Wolffian duct Wolffian tubules yolk
Fréquemment cités
Page 12 - ... greatest development. The following description is taken from that paper : " In the chick the glomerulus is paired and consists of a vascular outgrowth or ridge projecting into the body cavity on each side at the root of the mesentery. It extends from the anterior end of the Wolffian body to the point where the foremost opening of the head-kidney commences. We have found it at a period slightly earlier than that of the first development of the head-kidney. In the interior of this body is seen...
Page 87 - Salmon) obscured by some of the anterior haemal arches in the posterior part of the trunk being completed, not by the ribs, but by independent outgrowths of the basal parts of the haemal processes. In Elasmobranchii a still further divergence from the primitive arrangement is present. The ribs appear to have passed outwards along the intermuscular septa into the muscles, and are placed between the dorso-lateral and...
Page 87 - Salmon, renders their serial homology with the ventral parts of the haemal processes of the tail far less clear than in other types ; and further proof is required before such homology can be considered as definitely established. Under the third heading the skeletal elements supporting the finrays of the ventral lobe of the caudal fin of various types of fishes are •compared and the following conclusions are arrived at. (1.) The ventral lobe of the tail-fin of Pisces differs from the other unpaired...
Page 32 - Peripatus, though formed on a type of their own, more nearly resemble those of the Leech than of any other form with which I am acquainted. The annelidan affinities shown by their presence are of some interest. Around the segmental organs in the feet are peculiar cells richly supplied with tracheae, which appear to me to be similar to the fat bodies in insects.
Page 86 - ... stated by Gotte to be thickenings of a special cartilaginous investment of the notochord, which would seem to be homologous with that cartilaginous sheath which is placed in Elasmobranchii and Dipnoi within the membrana elastica externa. On the other hand, the development of the vertebrae of Lepidosteus is shown to resemble in most features that of Teleostei, from which it mainly differs in the presence of intervertebral cartilaginous rings. In the second section, devoted to the homologies of...
Page 49 - Cartilaginous arches beset with rays form the branchial skeleton. The form of skeleton of the appendages may be compared with them ; and we are led to the conclusion that it is possible that they may have been derived from such forms. In the branchial skeleton of the Selachii the cartilaginous bars are beset with simple rays. In many, a median one is developed to a greater size. As the surrounding rays become smaller, and approach the larger one, we get an intermediate step towards that arrangement...
Page 84 - A delicate layer of bone, developed in the perichondium, invests the cartilaginous neural arches, and this bone grows upwards so as to unite above with the osseous investment of separately developed bars of cartilage, which are directed obliquely backwards. These bars, or dorsal processes, may be reckoned as parts of the neural arches. Between the dorsal processes of the two sides are placed median rods of cartilage, which are developed separately from the true neural arches, and which constitute...
Page 49 - This differentiation of one ray, which is thereby raised to a higher grade, may le conriected with the primitive form of the appendicular skeleton ; and, as we compare the girdle with a branchial arch, so we may compare the median ray and its secondary investment of rays with the skeleton of the free appendage.
Page 31 - I have had an opportunity of making investigations on some well-preserved examples of Peripatus Capensis, a few of the results of which I propose to lay before the Society. I shall confine my observations to three organs. (1) The segmental organs, (2) the nervous system, (3) the so-called fat bodies of Mr Moseley. In all the segments of the body, with the exception of the first two or three postoral ones, there are present glandular bodies apparently equivalent to the segmental organs of Annelids....
Page 26 - Sci.,' in 1873 (p. 280), I made the following statement with reference to this subject : — " It is clear, therefore, that the primitive groove must be the rudiment of some ancestral feature. It is just possible that it is the last trace of that involution of the epiblast by which the hypoblast is formed in most of the lower animals.