GENERATIVE SYSTEM OF FISHES. 289 



capsules into the abdomen (b), and are excluded by the peritoneal aper- 

 tures (^ib. I). In all other fishes in which vasa deferentia are absent 

 in the male, oviducts are absent in the female. 

 But it does not always happen, where vasa de- 

 ferentia are developed in the male, that the 

 homologous ducts exist in the female : the Sal- 

 mon is an example in which the ova are dis- 

 charged by dehiscence into the abdominal cavity, 

 and escape by peritoneal outlets, as in the Eel 

 and Lamprey. 



With this exception, the parallelism of the 

 male and female organs is very close. Thus the 

 ovarium is single in those bony fishes, as the 

 Perch, the Blenny, the Loach and the Ammodyte 

 (prep. 2675. a), in which the testis is single : 

 Renal and Female Organs : ^he median clcft of the ovary of the Ammodyte is 



Feiromi/ion, Hunter. •' •' 



deeper than that of the testis, but the continuity 

 of the two seemingly distinct glands is obvious at the upper and lower 

 ends. Li most osseous fishes the ovaria form two elongated sacs of mu- 

 cous membrane, with a thin fibrous tunic and a peritoneal covering : 

 closed antei'iorly, but produced posteriorly into a short, straight, and 

 commonly wide oviduct, terminating behind the anus, and commonly 

 before the urethra. In the Pipe-fishes the oviducts continue distinct 

 to the cloaca. In most fishes the oviducts coalesce, sooner or later, 

 into a single tube before arriving at the cloaca : the common terminal 

 portion becomes much dilated in the Cod-fish, the Lump-fish, and 

 some others. The ' stroma,' or cellular tissue, which is the seat of 

 development of the ova, is interposed between the mucous and 

 fibrous tunics of the ovarian sac : it sometimes, though rarely, is co- 

 extensive with the raucous membrane. In the Lophius the two 

 ovaria are long and large plicated tubes, flattened when empty, cylin- 

 drical when inflated, with the ovigerous stroma lining, as it were, 

 only the ventral half of the walls of the cylinder, and terminating 

 where the oviducal portions of each sac unite together to form the 

 common short efferent canal. The inner surface of the 'stroma' is 

 beset by small tubercles, arranged in interrupted linear series, each 

 tubercle supporting four or five papilliform ovisacs. In the Pike the 

 stroma forms a longitudinal strip, in short ti-ansverse plaits, along the 

 median side of the long ovarian sacs. In the Wolf-fish the stroma 

 extends over the whole of the internal surface of the ovary, into the 

 cavity of which it projects in the form of numerous oval compressed 

 processes. In general, its superficies is extended by being plaited 



VOL. 11. u 



