466 COMPARATIVE ANATOMY 



in form, and consists of radially arranged tubules or of acini. 

 Its duct has similar relations to those seen in the female, arising, 

 however, not in the form of a simple tube, but as a network of 

 anastomosing canals, which usually open into the posterior end of 

 the kidney-duct. 



Thus the ducts, both of the ovary and testis, correspond to folds 

 of the peritoneum enclosing a coelomic cavity continuous with that 

 of the gonads, and originate quite independently of the nephridial 

 system. The oviducts must therefore be distinguished from true 

 Mullerian ducts. 



In some Teleosts, as in most other Fishes, the ovary is solid and 

 not enclosed in a coelomic sac, the ova being shed into the body- 

 cavity (" gymnoarian " condition). In the Smelt (Osmerus) and 

 in Mallotus the oviducts (" peritoneal funnels ") are not 

 continuous with the ovaries, but have open ccelomic apertures 

 close to the latter, into which the ova pass (cf. Fig. 350, B) ; while, 

 in other Salmcriidse and ; e.g., in the Mursenidse and Cobitis, these 

 peritoneal funnels are shorter, and may even be absent, the ova 

 then being shed into the urinogenital sinus through a paired or 

 single genital pore. 1 It is uncertain whether the latter is the 

 primitive arrangement amongst Teleostei, or whether the 

 peritoneal funnels represent reduced oviducts. In the Eel, a 

 similar reduction of the gonoduct is seen in both sexes. 



Hermaphroditism regularly occurs in certain Teleosts (e.g. 

 Serranus, Chrysophrys), and has been occasionally observed in some 

 others (e.g. Cod, Mackerel, Herring). 



Amongst Ganoids the female organs of Lepidosteus are 

 formed on the same type as those of the Teleostei. In Amia (Fig. 

 350, B) and Acipenser each oviduct opens by a wide funnel into 

 the coelome, but in all Ganoids each oviduct is probably com- 

 parable to that of Teleosts, and not to a Mullerian duct. In the 

 male Lepidosteus, Amia, and Acipenser, a series of vasa efferentia 

 pass out from the testis and open into a longitudinal canal from 

 which ducts enter the kidney, and then either communicate with 

 the Malpighian capsules, or else pass directly into the mesonephric 

 duct, which therefore serves as a urinogenital duct (Fig. 351). 

 In Lepidosteus the latter dilates before uniting with its fellow to 

 open into the urinogenital sinus. In Polypterus, there is a special 

 testis-duct comparable to that of Teleosts ; it is associated with a 

 network of cavities and opens into the posterior end of the kidney- 

 duct. Except in Lepidosteus, representatives of the oviducts of 



1 Most Teleostei are oviparous, but viviparous forms occur (p. 436). The 

 male Stickleback builds a nest for the protection of the young formed of a 

 hardened secretion (mucin) of the kidney, which thus undergoes a change of func- 

 tion at the breeding-season. In Syngiiathus and Hippocampus the young are pro- 

 tected within a pouch on the abdomen of the male, and in the female Soleno- 

 stoma in a pouch between the ventral fins ; amongst Siluroids they are carried 

 within the pharynx in the male Arius, and attached to the soft ventral integu- 

 ment in the female Aspredo. 



