FISHES — COTTIDAE — OLIGOCOTTUS. 



55 



also mucli higher than the anterior dorsal. The caudal is subtruncated or rounded posteriorly, 

 and constitutes a little less than the sixth of the entire length. The anterior ray of the anal 

 is situated opposite to the fourth ray of the second dor.sal. The tips of the posterior rays of 

 that fin terminate almost evenly with those of the dorsal, although its base does not extend 

 quite as far. The interradial membrane is, as usual, deeply emarginated. The tips of the 

 pectorals extend to a vertical line passing immediately in advance of the anal. The inferior 

 eight rays having their interradial membrane emarginated and are somewhat thicker than the 

 upper ones. 



Br. VI— VI ; D VIII, 21 ; A 17 ; C 4, 1, 5, 4, 1, 3 ; V I, 4 ; P 16. 



A 15; 5,1,4,4,1,4; 



P 1^ 



The head, a small area on each side of the anterior edge of the first dorsal, a narrow band on 

 each side of the base of the anal, a space about the caudal fin and the belly, are perfectly smooth. 



The rest of the surface of the body is densely beset with minute prickles, which in the young 

 are more developed above the lateral line than beneath it. The lateral line itself is very con- 

 spicuous, running straightway from the upper part of the thoracic arch to near the termination 

 of the second dorsal, hence, falling somewhat, reassumes a direct course to the base of the caudal. 



The ground color of the body, head, and fins, is olivaceous, maculated with blackish ; occasion- 

 ally the maculae, in running into each other, will assume a sinuous aspect, especially on the sides 

 of the head and towards the lower part of the fianks. The inferior regions are generally 

 unicolor, with the exception of the lower jaw over which the macula3 may extend. The fins 

 are all — some transversely, others obliquely — barred with a series of black confluent spots. A 

 conspicuous black patch is observed at the upper and posterior portion of the first dorsal. 



This species, like the preceding, inhabits the fresh waters of California. 



List of specimens. 



OLIGOCOTTUS, Girard. 



Gen. Chab. — Head smooth, with the exception of a few spines upon the preopercle and snout. Upper jaw slightly the 

 longest. Teeth upon the premaxillaries, dentaries, front of vomer, and palatines. Gill openings continuous under the 

 throat ; branchiostegals, six. Anterior dorsal lower than the posterior. Caudal posteriorly rounded. Insertion of 

 ventrals backwards of the base of pectorals. Skin smooth or slightly prickly. Lateral line continuous for the whole length 

 of the body. 



SxK.—OligocoUus, Grd. Proc. Acad. Nat. Sc. Philad. Vni, 1856, 132. 



The genus which we institute under the above denomination is the smallest we know of in 

 the cottoid group, the stickle-backs excepted. It bears close affinities to both Leiocotius and 



