On the Urogenital Ajyparatus of a Blennioid Fish. 403 



XLIV. — On the Urogenital Apparatus of a Blennioid Fish 

 from Tasmania, By Dr. Albert Gunther, F.E.S. 



The so-called urogenital or anal papilla is, as is well known, 

 most conspicuous in the Gobiidte and Blennidge, although not 

 exclusively confined to those families. In some of the genera 

 it is a sexual character ; in others it is almost as much developed 

 in the female as in the male. In Clinus despicillatus^ from 

 South Australia and Tasmania, it is a sexual character, the 

 female showing in its place merely a simple short perforated fold 

 of the skin. But the male of this species has it developed in a 

 very extraordinary manner ; and, more especially, the internal 

 portion of the duct shows a very singular structure, which 

 does not appear to have been recorded hitherto. In a specimen 

 14| inches long* the papilla lies with the vent in a rather deep 

 circular hollow, and is encircled by a loose fold of the skin. 

 The papilla itself consists of two parts — a posterior tapering- 

 portion, perforated at its extremity and 5 lines long, and 

 an anterior shorter and broader portion longitudinally grooved 

 behind, the posterior portion fitting into the groove. The 

 anterior portion would appear to form a support to the pos- 

 terior during the act of fecundation. 



On opening the abdominal cavity we find that the common 

 canal for the vasa deferentia and the urethra is not a simple 

 membranaceous tube, but on its ventral surface overlaid with 

 an extremely thick muscular mass, the whole organ having 

 the shape and size of a very large bean, the muscle forming 

 the convex portion, whilst the canal runs along the concave 

 posterior margin. This muscle in a longitudinal section is 

 6 lines thick in its middle ; its outer surface is covered by a 

 shining tendinous layer, which, becoming thicker towards the 

 vertebral column, is finally attached to the base of the anterior 

 haemal spine. The muscular fibres take their origin from the 

 tendinous sm-face of the organ. 



The canal, which in the external papilla is very narrow, 

 widens considerably within the abdomen ; and its cavity is 

 occupied by a complex network of loose fasciculi rising from 

 the mucous membrane with which the cavity is clothed, but 

 leaving an open main channel along the middle of the cavity. 

 The effect of this arrangement is obvious : the semen accumu- 

 lates first in the wide and spongy cavity of the common duct ; 

 this is compressed by the muscle, the fluid being thus ex- 



* For this, as well as a female of the same size, I am indebted to Morton 

 Allport, Esq., of Hobart Town. 



97* 



