52 MONOGRAPH OP THE FRESH WATER III. 



feature not being exhibited in the figure. The insertion of the ventrals takes place 

 in advance of the anterior dorsal, and behind the base of the pectorals. The two 

 inner rays are the longest, as seen in the enlarged figure of these fins beneath Fig. 

 1. They do not reach the anus when bent backwards. The pectorals are of 

 medium size, shorter than the head, composed of twelve unbranched rays. The 

 membrane is deeply notched on the outer edge of the seven lowermost rays. Their 

 base of insertion is nearly straight. When bent backwards they scarcely reach the 

 anterior margin of the second dorsal, and leave the anal behind. 



Br. 6. D VIII. — 17. A 12. C 4. I. 5. 4. I. 3. V I. 3. P 12. 



The lateral line is slightly inflexed on the abdomen, but runs straight along the 

 back until the posterior extremity of the second dorsal, when the fall takes place 

 obliquely towards the centre of the peduncle of the tail, and straight again to the 

 base of the caudal. The series of pores commences under the tenth ray of the 

 second dorsal. 



The anus is situated a little nearer the end o{ the snout than the extremity of 

 the caudal fin, consequently nearer the base of that fin than the snout. 



The color is thus described by Prof Haldeman : " yellowish, clouded with black, 

 the first dorsal fin edged with a narrow line of orange." 



The following information respecting the habits of this species, is from the 

 notes of Professor Baird : — 



These fish usually inhabit clear, spring waters, especially the spring runs 

 which flow through rich meadows, bordered by turf, and having a shallow pebbly 

 bottom. They lie concealed under projecting clods, flat stones, boards, or what- 

 ever may serve their purposes of concealment. On being disturbed, they usu- 

 ally hasten off to fresh cover, but sometimes remain motionless. Occasionally 

 they occur in larger bodies of water, of less purity; but we have never seen them 

 in creeks or rivers. Sometimes they are seen lying close to the edge of rivulets 

 formed by leaking embankments, and where the water is far from clear. They 

 always lie close to the bottom, and are never seen poised in the water. 



The eggs are laid from the middle of April to the end of May, and are deposited 

 in round packets about the size of an ounce bullet, under boards, stones, and in 

 shallow, springy water. It is possible that they are watched by the parent, as we 

 have frequently found individuals under the same cover as the eggs. The ova are 

 of a rose color, and about the size of No. 3 shot, conveying the impression of dis- 

 proportionate size. Occasionally, we have found the eggs with embryos moving 

 freely within the envelope. A set examined April 22d, 1848, had the eye very dis- 

 tinct, and of large size. The foetal fin extended from the head, by the tail, to the 

 anus. In the course of the day, many became liberated, and swam about with 

 the yolk bag attached. This was sessile, and filled with a transparent, reddish 

 liquid, excepting opposite to the embryo, where was a hard, yellowish cake. All 

 our attempts at raising the young, or of development of the egg, failed for want 

 of fresh spring water. 



The body is the most slimy amongst the known species, whence its name visco- 

 Bus, which we think is well appropriated. Specimens have been collected by Prof 



