Elements of comparative anatomy (1878) Elements of comparative anatomy elementsofcompar00gege Year: 1878 014 COMPARATIVE ANATOMY. commence by a wide abdominal month. The mucous membrane which invests them is set in a number of longitudinal folds; the lower portion, in addition to the greater thickness of its muscular wall, is distinguished from the other and longer portion by the larger size of its folds and villi; this is especially the case in Birds. This differentiation of the oviduct corresponds to the different function of the different parts; the longer and more anterior portion secrete
Elements of comparative anatomy (1878) Elements of comparative anatomy elementsofcompar00gege Year: 1878 014 COMPARATIVE ANATOMY. commence by a wide abdominal month. The mucous membrane which invests them is set in a number of longitudinal folds; the lower portion, in addition to the greater thickness of its muscular wall, is distinguished from the other and longer portion by the larger size of its folds and villi; this is especially the case in Birds. This differentiation of the oviduct corresponds to the different function of the different parts; the longer and more anterior portion secretes the albumen, and the thick-walled terminal part forms the shell. This portion is connected by a short and narrower piece with the cloaca. In correlation with the atrophy of the right ovary the oviduct of the same side is also atrophied in Birds; not unfrequently, however, remnants of it are found near the cloaca. While the oviducts open by one orifice in the Ophidii and Saurii, as well as in Birds, in the Chelonii they open into the neck of the so-called urinary bladder; this foreshadows the relation which is the typical one among the Mammalia. In many Ophidii a diverticulum of the posterior wall of the cloaca receives the openings of the oviducts. A remnant of the primitive kidney is retained behind the ovaries (this has been observed in the Saurii and Aves). The testes, which are gene- rally oval, are attached to the vertebral column by a fold of the mesenteries; this is either effected in front of, or between the kidneys. Their size is closely correlated with their physio- logical activity; this is especially the case in Birds. In the Ophidii they are arranged in the same way as the ovaries. The vasa efferentia pass to a parorchis, which generally consists of a few canals only, and from which a vas deferens extends to the cloaca. In the Crocodilini it is straight, in the Ophidii, Saurii, and Aves it is arranged in a number of smaller coils, while in the Chelonii (Fig. 349,
Size: 1067px × 1875px
Photo credit: © Bookworm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
