44 MONOGRAPH OF THE FRESH WATER III. 



Their tip will reach backwards, the origin of the second dorsal only, thus propor- 

 tionally shorter than those of G. Bairdii. 



Br. 6. D VII. — 16. A 13. C 2. I. 4. 4. I. 2. V I. 4. P 14. 



The vent is situated under the second ray of the second dorsal. 



The lateral line is nearly straight, and can be traced to the base of the caudal. 

 The cartilaginous capsules, however, disappear under the fourteenth ray of the 

 second dorsal, whilst the fall takes place under the last ray. Its peculiar appear- 

 ance in the specimen figured, is owing, as already observed, to the decomposed state 

 of the epidermis, rendering the holes of the dermic layer more conspicuous. 



The accompanying figure is the only one which was not drawn by Mr. Sonrel, 

 from nature. Our sketch was made originally with a mere view of giving the 

 striking character of the bifurcation of the pectoral fins. 



Specimens of this species, the largest measuring only three inches and five- 

 eighths, were sent to the Smithsonian Institution, by Prof. L. D. Williams of 

 Meadville, and collected by that gentleman in French Creek (Pa.) . 



The ground color of these is yellowish-green, intermingled with cloudy patches 

 of brownish-black. The base of the caudal is black. All the fins, the ventrals 

 excepted, are banded with black. The latter have the uniform palish-yellow of the 

 belly. 



Prof. Baird's specimens were collected by himself in a tributary of the Alleghany 

 Eiver, at Poxburg (Pa.). 



IV. COTTIJS BAIRDII, Girard. 

 Plate I. Figs. 5 and 6. 



Syn. Oottus Bairdii, Girard, Proc. Amer. Assoc. Adv. Sc. II. 1850, p. 410; and, Proc. Bost. Soc. Nat. 

 Hist. III. 1850, p. 189. 

 Cottus (johio, KiRTL. Bost. Journ. Nat. Hist. V. 1847, p. 342. 



This, amongst all the species represented on our plates, is the one which has the 

 most elegant shape. The uniform declivity of the snout, passing gradually over 

 the eyes, and backwards to the tail, without the slightest deviation from a slightly 

 concave or almost straight coui"se, contributes to that elegance, rendered more per- 

 fect by a similar outline of the belly. Now, as the body tapers very gradually 

 away towards the tail, together with the thickness, the general form is still im- 

 proved by these proportions of height and breadth. So we might call the general 

 form, elongated, although at first sight it will strike us as being rather short, espe- 

 cially when compared to C. viscosibs. 



The greatest depth of the body, taken at the origin of the first dorsal and ventral 

 fins, enters only six times and a half in the total length, and the least depth, in 

 advance of the caudal, is contained in it nearly fourteen times and a half. The 

 greatest thickness is equal to the depth ; but it diminishes more rapidly backwards, so 

 that, on the peduncle of the tail, the thickness is reduced to one-half of the depth. 



The head forms the third of the length of the fish, the caudal fin excluded; it 

 is one-third longer than broad, and less obtuse on the snout than in G. viscosus. 



