TION. 



Class IV. BLACK GOBY. 239 



acquainted with two species ; one a sea fish 

 that frequented the rocks, another that was 

 gregarious, and an inhabitant of rivers, which 

 last seems to have been our common gudgeon. 



This species grows to the length of six inches; Descrip* 

 the body is soft, slippery, and of a slender form; 

 the head is rather large ; the cheeks inflated ; 

 the teeth small, and disposed in two rows ; from 

 the head to the first dorsal fin is a small sulcus. 

 The first dorsal fin consists of six rays; the 

 second of fourteen ; the pectoral fins of sixteen 

 or seventeen, closely set together, and the mid- 

 dlemost the longest; the others on each side 

 gradually shorter ; the ventral fins coalesce and 

 form a sort of funnel, by which these fish affix 

 themselves immoveably to the rocks, for which 

 reason they are called rock-jish ; the tail is 

 rounded at the end. The color is brown, or 

 deep olive, mixed with dark, and spotted with 

 black; the dorsal and anal fins are of a pale 

 blue, the rays marked with minute black spots. 



VOL. III. 



