REPTILES. 223 



The organs for preparing the germ and the seed (ovaries and 

 testes) are always in pairs, mostly of the same size and placed 

 symmetrically on the two sides. In the serpents, however, and in 

 the genus Proteus the right ovarium and the right testis lie more 

 forward than the corresponding organs on the left side, which often 

 also are less. The oviducts are never, as in many bony fishes and 

 in invertebrate animals (see above, p. 38), immediate continuations 

 of the ovary, but have free openings into the cavity of the abdomen, 

 as for instance in batrachians, where they are situated in the up- 

 permost part of the abdominal cavity close to the heart ; here 

 the oviducts are very tortuous, and have when straightened out a 

 length of more than two feet. The lower ends of the oviducts exhi- 

 bit thicker walls, and have, especially in the species that are vivi- 

 parous, as the land-salamanders, a great width. In the frogs the 

 lower apertures of the tubes terminate in a membranous sac capable 

 of much distension from the eggs, and to wliich the scarcely appro- 

 priate name of uterus has been given. In the tortoises the inferior 

 apertures of the ovaries are situated near the neck of the urinary 

 bladder, at the upper part of the cloaca. 



The ovaries have the form either of sacs, — which in the tailed 

 diplopioa are undivided, but in the batrachians, serpents and 

 lizards are divided into cells, — or of laminse, on the abdominal 

 surface of which the eggs are developed, and when ripe are 

 separated, as in the crocodiles and tortoises. 



The testes lie on each side of the spinal column, in front of the 

 kidneys in lizards and sei-pents, in batrachians on the fore part 

 of the kidneys, in chelonians on the hind part of the same, which 

 are always situated more towards the back. In the salamanders the 

 testes are divided into roundish bodies, sometimes different in 

 number on the opposite sides (two, three or four), placed behind 

 one another. 



The arrangement in frogs, already noticed by Swammerdam, is 

 remarkable, viz. that the ureters are also the efferent vessels \ In 



1 Bijbel der nat. pp. 795, 796. What Rathke and others supposed to be a 

 vas deferens distinct from the ureteres, is, according to Bidder, a communicating 

 vessel covered with dark pigment forming an anastomosis between the iliac artery and 

 the axillary; F. H. Bidder Vergleichend-anatomische u. histologische Untersuchungen 

 iiber die mdnnliche Oeschlechts- und Harnwerlczeuge der nacMen Amphibien. Dorpat, i84f>, 

 4to, s. ■21, 



