SILURUS (PARASILURUS) ARISTOTELIS. 57 



angle of the mouth. A broad interspace, more than half 

 the diameter of the eye, interrupts the narrow band of 

 vomorine teeth in the middle; they might be described as 

 two short transverse bands, the length of each of which 

 is a little more than twice its width. In the first series 

 the gill-rakers are short, sharp, rigid, not as long as the 

 eye, and vary in number from twelve to fifteen. The dor- 

 sal fin is very slender, having only three rays, and is situ- 

 ated at about two-sevenths of the distance from the snout 

 to the end of the tail, or a little in front of the hinder ex- 

 tremities of the pectoral spines if they are applied to the 

 sides. There is no adipose fin. The anal fin is long, 

 nearly four-sevenths of the length, without the caudal, and 

 contains, in most cases, more than seventy rays. One of 

 the individuals in hand has only sixty-seven. At the end 

 the caudal fin is rounded or subtruncate ; generally it has 

 eighteen rays, rarely there are nineteen ; it is united with 

 the anal less than half its length. The ventrals are farther 

 back than the dorsal ; on four specimens there are nine rays 

 in each ventral fin, on two others there are ten rays in each, 

 and one has ten rays in one ventral and but nine in the 

 other. In length the pectoral tins equal the distance from 

 the eye to the end of the opercle ; they are broadly round- 

 ed on the posterior margin, and most often contain one 

 spine and eleven rays ; rarely the number of rays is twelve. 

 The spine is strongly compressed ; the teeth on its hinder 

 edge are sharp pointed and comparatively large, those in 

 front are distinct but smaller. 



The coloration of the back and of the top of the head 

 is brownish, of the sides silvery with rather coarse brown 

 puncticulations arranged in irregular nebulous groups 

 which approximate to blotches along the base of the anal 

 and on the anterior half of the caudal. 



The description is taken from specimens in the Museum 



ESSEX INST. BULLETIN, VOL. XXII 4* 



