MALE ORGANS OF FISHES. 



5G9 



Renal and male organs : 

 Trigla lyra, Carus 



extending backward into a kind of concealed scrotum 



integuments 



379 



are distinct from each other, but their ' vasa deferentia ' almost 

 immediately unite into a common duct, e, which joins the urethra, 

 c, behind the rectum, h, and terminates at the 

 outlet, g. In the Salmon and the Herring the 

 * vasa deferentia ' do not unite together until 

 near their termination in the urethra. In the 

 Cod and the Bull-head ( Cottus) the common 

 portion of the efferent duct is much dilated : 

 it forms a saccular seminal reservoir in the 

 Sole. The canal common to the ureter and 

 vas deferens is of great length in the Sturgeon : 

 a valve prevents the regurgitation of the urine 

 into the spermatic duct. The urethra is usually 

 produced into a papilla, which projects con- 

 spicuously from the back part of the cloaca in 

 the viviparous Poecilia, Anableps, and Blenny : 

 it is large also in the Lump-fish. The testes are almost 

 entirely extra-abdominal in the Flounder and some other Pleu 

 ronectidce 

 between the 



and muscles on each side 

 above the anal fin. The 

 testes differ much in form 

 in different Osseous Fishes, 

 but are remarkable in all 

 for their enormous seasonal 

 increase : when fully deve- 

 loped, they are commonly 

 known as the ' milt ' or ' soft 

 roe.' In Gymnotus they are 

 two oblong triedral bodies, 

 attenuated at both ends. 

 In the Pipe-fishes (Syn- 

 gnathi) they present the form 

 of two simple elongated 

 straight tubes, fig. 427 , 

 g 3. 1 In the Lump-fishes 

 ( Cyclopteri) they are di- 

 vided by incisions into 

 lobes : in the Cod a vast 

 extent of the vascular sur- 



Structure of the testis in Clupea Alosa. cxxil. 



face of the 



glandular 



substance is packed into a small com- 



1 xx. vol. iv. p. 48, prep. no. 2375. 



