576 ANATOMY OF VERTEBRATES. 



cotyledons developed from the internal surface of the dilated pari 

 of the oviduct : corresponding foetal cotyledons are developed 

 from the vitelliclc of the embryo. 



Thus the various forms of the generative organs of Fishes 

 resolve themselves into four well-marked grades of complexity. 

 First, the essential gland, testis or ovarium, "without excretory 

 canal. Second, the same, with a simple duct, continuous with 

 testis or ovarium. Third, a partial oviduct, not continuous with 

 the ovarium, and not separated from the ureter. Fourth, testis 

 or ovarium, of a more compact form, each with a long and 

 complex duct, distinct from the ureter ; the beginning of the 

 vas deferens convoluted into an epididymis, and its end dilated 

 into a seminal reservoir, with a plicated glandular inner surface : 

 the oviduct not continuous with the ovarium, but with a nida- 

 mental gland near its commencement, and dilating into a 

 receptacle, with a plicated surface, at its terminal half. Besides 

 the 'elaspers' of the Plagiostomes, there are other accessory 

 organs of generation, viz. the subcaudal marsupial tegumentary 

 folds in the male of some species of Syngnatkus, fig. 427, o, 1 and 

 the subabdominal marsupial pouch in the male Hippocamps. 2 



§ 108. Male Organs of Batrachians. — These consist of testes, their 

 ducts and appendages, the seminal reservoir, and the common ex- 

 cretory canal and terminal papilla : there is no intromittent organ. 



The testes, though in some Batrachia subdivided, resemble in 

 their relative size and compactness of form and tissue those of the 

 Plagiostomes. In the Proteus anguinus the testis is long, cylin- 

 drical, with obtuse ends, slightly fissured lengthwise by the 

 insertion of the suspensory ligament : they sometimes show in- 

 equality of size, and the right is usually about three vertebra' 

 in advance of the left. In Amphiuma the testis is subcylin- 

 drical, and tapers at both extremities : adipose appendages project 

 from their free or ventral surface. In the Axolotl the ' mesor- 

 chium,' or suspensory duplicative of peritoneum, is broader, and 

 permits the vessels and ducts to be readily seen as they traverse 

 it transversely. The adipose appendages are branched In the 

 Menopome the testes are rather broader than in the Amphiume, 

 approaching the oval shape. This is likewise the case, with 

 one or both testes of the great Japan Newt (Sieboldtia or 

 Cryptobranchus), which are suspended by a broad mesorchium 

 on each side of the aorta and narrow remnants of the Wolffian 

 bodies, between the ends of the lungs aud the beginnings of the 

 kidneys. 



1 xx. vol. v. p. 67, preps, nos. 3226-3228. 2 lb. p. 68, preps, nos. 3230 and 3231. 



