58 MONOGRAPH OF THE FRESH WATER III. 



a quarter, was first collected at Windsor (Vt.), by Ed. Cabot, Esq., of Boston. 

 Dr. D. H. Storer had in his possession two small ones from the same vicinities. 



Specimens are preserved in Prof. Agassiz's Cabinet, and at the Smithsonian In- 

 stitution. 



XII. COTTtJS FORiWOSUS, GIRARD. - 



Amongst the macerated remains of Triylopsis Thompaonii, described further on, 

 we detected the body of a Cottus, in a similarly mutilated state. After instituting 

 all the comparisons which could possibly be made, we became fully satisfied that 

 we had to deal with a distinct and undescribed species, although not quite prepared 

 to give a full and satisfactory description of it. Its most striking peculiarities are 

 a small head, a slender and graceful body, with the two dorsals widely separated. 

 The entire length, from the snout to the extremity of the caudal fin, is three inches 

 and a quarter, in which length the head enters for about the fifth part. The upper 

 surface of the head is very flat, and the eyes of medium size, circular, and very 

 proportionate. The anterior and inferior part of the head are destroyed in the 

 specimen under examination, so that we are at a loss to describe the nostrils, the 

 shape of the mouth, the isthmus, as well as to state how many times the diameter 

 of the eye is contained in the length of the head. The preopercular spine is stout 

 and rather short, acute, and curved. There exists on the same bone a small 

 spine, situated under the first, and directed obliquely downwards and backwards. 

 The subopercular spine is well developed, acute, and curved upwards, being as 

 usual directed forwards. The greatest thickness, and depth of the body cannot 

 be given under the existing circumstances ; but the least depth, taken on the 

 peduncle of the tail, is contained nearly eighteen times in the total length, being 

 about three-sixteenths of an inch. The body itself seems to have been regularly 

 fusiform. 



The anterior edge of the first dorsal is situated at thirteen-sixteenths of an inch 

 from the snout. It is composed of eight rays, extending on a basis of half an 

 inch. Its upper edge is regularly arched. The second dorsal is separated from the 

 first by a space of nearly a quarter of an inch, filled by a membrane which extends 

 between both fins. The rays, sixteen in number, are very slender and unbranched, 

 the two anterior ones shorter than the third. There is a free space of a quarter of 

 an inch between the posterior end of the second dorsal and the base of the caudal 

 fin. The caudal itself is rounded posteriorly, convex, composed of eleven rays, and 

 a few rudimentary ones; those of the middle of the fin, are branched towards their 

 extremity ; its length is contained six times and a half in the total lenirth. The 

 origin of the anal takes place under the third ray of the second dorsal, and leaves 

 a space of nearly half an inch between its posterior end and the beginning of the 

 caudal. The ventrals are situated under the pectorals, in advance of the anterior 

 dorsal; when bent backwards, they are very far from reaching the vent. The l>as.- 

 of the pectorals is crescent-shaped and very close to the <i\\\ openings. These (ins 

 are rather short, composed of twelve or thirteen unhranched rays, and when bent 



