SILURUS (PARASILURUS) ARISTOTELIS. 57 
anglo ol' tlio mouth. A hi-oud interspace, more than half 
the diameter of the eye, interrupts the narrow band of 
vomerine teeth in the middle ; they might he 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 tifteen. The dor- 
sal tin is very slender, having only thi'ce rays, and is situ- 
ated at about two-sevenths of the distance from the snout 
to the end of the tail, or u little in front ot the hinder ex- 
tremities of the pectoral spines if they are applied to the 
sides. There is no adipose tin. The anal tin 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. 
Tiie 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 In-ownish, 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. XXU 4* 
