MALE ORGANS OF FISHES. 



5G9 



379 



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

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

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

 outlet, y. In the Salmon and the Herring the 

 6 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, Avhich projects con- 

 spicuously from the back part Of the Cloaca in Renal and male organs : 



the viviparous Poecilia, Anableps, and Bleimy : 



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



entirely extra-abdominal in the Flounder and some other Pleu- 



ronectidcB, extending backward into a kind of concealed scrotum 



between the integuments 



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 f milt ' or ( soft 

 roe.' In Gymnotus they are 

 two oblong triedral bodies, 

 attenuated at both ends. 

 In the Pipe-fishes (Syn- 

 ynathi) they present the form 

 of two simple elongated 

 straight tubes, fig. 427 , 

 g 3. 1 In the Lump-fishes 

 (Cyclopterf) they are di- 

 vided by incisions into 

 lobes : in the Cod a vast 



/ . -, -i Structure of the testis iu Clupea Alosa. cxxn. 



extent ot the vascular sur- 

 face of the glandular substance is packed into a small com- 



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



