40 MONOGRAPH OF THE FRESH WATER III. 



The fins in general are well developed. The first dorsal is composed of eight 

 rays inserted on a basis of six-eighths of an inch ; its anterior edge is at a distance 

 of an inch and a half from the extremity of the snout. Its upper edge is sub- 

 convex j the fourth, fifth, and sixth rays being the highest. The second dorsal, 

 twice as extended as the first and one-third more elevated than the latter, is com- 

 posed of eighteen rays, the highest being situated in the middle of the fin and 

 slightly dichotomized at their extremities. The membrane of the first dorsal reaches 

 the first ray of the second, so that these two fins may be said to be continuous, 

 although a very deep notch still exists between them. The caudal fin, six-eighths 

 of an inch in length, is truncated posteriorly ; its upper and lower' edge are slightly 

 convex. It contains thirteen full-developed rays with some rudimentary ones ; the 

 four middle ones, bifurcated from their very base, dichotomize again on the last 

 fourth of their length, together with the two adjoining rays, on either side. The 

 anal fin commences under the third ray of the second dorsal and terminates a little 

 before the last, although the posterior extremity of the rays of the first extends a 

 little more backwards. In shape, it differs from the second dorsal in being more 

 convex, in having a lower membrane, and, consequently, the tips of the rays ex- 

 tending free beyond it to a greater length. There are fourteen undivided rays. 

 The ventral fins are composed of five rays, a spiny one situated at the outer edge 

 and closely connected to the second (the first soft one) but much shorter. 

 The remaining four are soft and articulated but undivided, the two middle ones 

 being the longest, as shown by the enlarged figure of the left fin beneath Fig. 1. 

 The pectorals are comparatively moderate in size. The rays are fifteen in number, 

 and all undivided. The longest occupy the upper third of that fin and are 

 more slender. Their length is only six-eighths of an inch, consequently much 

 below the length of the head. The base of insertion, seen exteriorly, is crescent 

 shaped. The formula of the fins is as follows : — 



Br. 6. D VIII. — 18. A 14. C 3. I. 5. 6. I. V I. 4. P 15. 



The vent being exactly situated on the middle of the total length, the caudal fin 

 included, is consequently nearer the base of insertion of the caudal than the 

 extremity of the snout. It is bordered posteriorly by a small, lanceolated, tongue- 

 like membrane which lies against the anterior ray of the anal. 



The lateral line is very conspicuous ; it bends itself slightly down on the abdomen 

 to follow afterwards a straight course to the fifth ray of the second dorsal, where 

 the cartilaginous subcutaneous plates cease and minute pores alone exist to con- 

 tinue it inconspicuously to the base of the caudal fin. 



The color, so far as we can judge from dead specimens, is of a dark olivaceous 

 brown on the back and sides, blackish on the head, cheeks, and lower jaw. The 

 lower part of the sides is lighter ; the belly and lower part of the head reflect 

 rather a yellowish hue with scattered small black spots. The general color of the 

 fins is the same as the region to which they belong; they are maculated and dotted 

 with black or brown. In the young, the spots are spread all over the body, which 

 give to it a marbled or maculated appearance. 



The characters by which this species is distinguished from C. cognahis, as far, at 



