326 PROCEEDINGS OF THE ACADEMY OF 



pectorals long, narrow and subqnadrangular, the ventrals long, narrow and 

 tapering ; anal twice as long as broad, quadrangular. 



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The fin-rays are D, 9. C, 20 - P, 14. V, 8. A, 7. 



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Color. In alcoholic specimens, the whole head, posteriorly to the nape of 

 the neck, inky black. The opercle occasionally with a metallic reflection. A 

 black narrow band extends from opercle to caudal fin, above lateral line 

 anterior and below, posterior to dorsal fin. Body of a general gray hue, 

 darker on the back, and yellowish on the belly. A narrow black line on 

 peduncle of tail. 



Total length 2 inches. 



The specimens from which the description is taken, were procured by Dr. 

 .T. H. Slack, of Philadelphia, in June, 1860, at Lake Whittlesey, Minnesota. 

 From the number of specimens obtained, it is natural to suppose that it is, 

 in that district at least, a very numerous species. 



2. Cottus C opei Abbott. Body subcylindrical ; its greatest depth is con- 

 tained six times in the entire length from snout to tip of caudal fin ; and the 

 least depth, at insertion of caudal fin, is contained thirteen times in the 

 entire length. Head twice as broad as deep, with its frontal length equal to 

 its width. The snout is obtuse. A vertical line drawn upwards, from the angle 

 of the mouth would pass anterior to the pupil. The eyes are circular, 

 medium sized, and the diameter is contained little more than four times in 

 the length of the head. The preopercular spine is strongly developed, curving 

 slightly upwards. A small acute spine on the subopercle. The gill openings 

 are oblique, large and separated under the throat by an isthmus of three- 

 eighths of an inch. The lateral line is distinct throughout its course ; it is 

 concurrent with the dorsal outline. The first ray of the dorsal is inserted 

 fifteen-sixteenths of an inch from the extremity of the snout, and extends on 

 a basis of one-third of an inch ; the origin of second dorsal is posterior to the 

 vent, the first and last rays shorter than the middle ones. The commence- 

 ment of anal fin is opposite the third ray of dorsal. The caudal fin is rounded 

 X>osteriorly, and is contained six times in the entire length ; the middle rays 

 are bifurcated. The ventrals are inserted in a line with the centre of the in- 

 sertion of pectorals ; the tips of rays do not reach the anus, if bent backward. 

 The bases of the pectorals are crescent shaped, and the tips of the rays, if 

 bended backward, will reach the first ray of second dorsal, but not the anal 

 fin. 



The number of fin rays are D, 715. P, 12. V, 8. C,"14. A, 10. 



Color. Head and back of a varied blackish-gray, with minute yellow spots ; 

 sides yellowish-gray, fading to pearly white on the belly ; sides marked with 

 very irregular dark gray lines. The fins partaking the color of the region to 

 which they belong, are sparingly dotted with deep black. Iris bronze. 

 Total length 3f inches. 



Habitat. A small trout stream, a tributary of a tributary of Brandywine 

 creek, Chester Co., Pennsylvania. But one adult and one young specimen 

 captured. 



I dedicate, with much pleasure, this beautiful Cottus, to Mr. E. D. Cope, of 

 Philadelphia, by whom it was found, and kindly loaned me for description. 



PCECILOSOMA, Agass. 

 Gen. Char. Head short and strong, rounded. Mouth little opened, pro- 

 portionately broad ; it is not protractile, though the maxillary bone be move- 

 able ; opercular apparatus scaly ; cheeks bare. 



3. P. transversum Abbott. Head and body compressed ; nose acute. 

 Operculum terminating in a spine posteriorly. Jaws equal ; mouth broad. 

 Margin of jaws armed with very numerous, small, inwardly curved, sharp 

 teeth. The origin of the first dorsal fin is posterior to the insertion of pectoral 



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