The Works of Francis Maitland Balfour ..., Volume 1Macmillan and Company, 1885 |
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The Works of Francis Maitland Balfour ..., Volume 1 Francis Maitland Balfour Affichage du livre entier - 1885 |
Expressions et termes fréquents
adult alimentary canal Amphioxus anus appears become blastoderm blastopore body-cavity brain branch caudal cloaca columnar commencing completely connected continuous derived distinct Dog-fish dorsal Elasmobranchs embryo epiblast folds formation formed front ganglion Ganoids germinal disc germinal epithelium germinal vesicle Götte granular hæmal arches head-kidney hypoblast involution kidney lateral Lepidosteus lobes longitudinal sections lower layer cells lumen mass medullary groove membrane mesoblast Müllerian duct muscle-plates neural canal notochord nuclei observations ocul opening organs origin Osseous fishes ovary oviduct ovum pellucid area Plate portion posterior roots present primitive groove primitive streak Pristiurus processes protoplasm protovertebræ region rudiment Scyllium seen segmental duct segmental tubes segmentation cavity Selachians separated shew shewn side specimens spinal cord spinal nerves splanchnic splanchnopleure stage stroma structure surface tail Teleostei thickened tissue transverse sections ureters vasa efferentia ventral vertebral vide visceral clefts wall Wolffian body Wolffian duct yolk Zeiss
Fréquemment cités
Page 706 - Balfour, early embryological changes imply that — " the functions of the central nervous system, which were originally taken by the whole skin, became gradually concentrated in a special part of the skin which was step by step removed from the surface, and has finally become in the higher types a well-defined organ imbedded in the subdermal tissues. . . . The embryological evidence shows that the ganglion-cells of the central part of the nervous system are originally derived from the simple undifferentiated...
Page 237 - An average specimen of the larger cells of the lower layer measures about f^ in. in diameter, and is therefore considerably smaller than one of the smallest cells of the last stage. The formation of fresh segments from the yolk still continues with fair rapidity, but nearly comes to an end shortly after this. Of the nuclei of the lower layer cells, there is not much to add to what has already been said. Not infrequently two nuclei may be observed in a single cell. The nuclei in the yolk which surrounds...
Page 660 - Grube as a lateral canal, is in reality a glandular tube, lined by beautiful columnar cells containing secretion globules, which opens by means of a non-glandular duct into the mouth. It lies close above the ventral nerve cords in a lateral compartment of the body-cavity, and extends backwards for a varying distance. This organ may perhaps be best compared with the simple salivary gland of Julus. It is not to be confused with the slime glands of Mr. Moseley, which have their opening in the oral papillae....
Page 24 - Bitter constraint and sad occasion dear Compels me to disturb your season due; For Lycidas is dead, dead ere his prime, Young Lycidas, and hath not left his peer.
Page 921 - The blastopore has completely closed in its middle portion and given rise to two openings, the embryonic mouth and anus. The anterior pair of somites have moved to the front end of the body, and the primitive groove is very marked.
Page 658 - ... in stained preparations by the intensity with which the nuclei of its walls absorb the colouring matter. The segmental organs of 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 879 - They are essentially short papillae, moved by an elaborate and powerful system of muscles, and armed at their free extremities by a pair of cutting blades or claws. The latter structures are, in all essential points, similar to the claws borne by the feet, and, like these, are formed as thickenings of the cuticle. They have, therefore, essentially the characters of the claws and jaws of the Arthropoda, and are wholly dissimilar to the setae of Chcetopoda.
Page 713 - The discovery that nerves have been developed from processes of epithelial cells, gives a very different conception of their genesis to that of Herbert Spencer, which makes them originate from the passage of nervous impulses through a tract of mingled colloids...
Page 537 - I would suggest that in the formation of the polar cells part of the constituents of the germinal vesicle, which are requisite for its functions as a complete and independent nucleus, is removed, to make room for the supply of the necessary parts to it again by the spermatic nucleus.
Page 851 - Wolffian body, which are usually separated from each other by a more or less considerable interval, it was a matter of no very great importance to know whether the anterior part of the socalled kidney was a true excretory organ. In the present state of our knowledge the question is, however, one of considerable interest.