HYPOSTOMA PLECOSTOJIUS. 189 



(" c'est souvent sur le dos qu'ils nagent"). They 

 feed on worms, and spawn in September, eggs 

 which are attached to the rocks by a gluten."* 

 Again, in speaking of the Hypostome de Commer- 

 son, which occurred in the whole courses of the 

 Parana and the Uruguay, " they never quitted the 

 stony or rocky parts of the rivers, and when the 

 waters fell they are taken in holes or under insu- 

 lated stones; at Corrientes they squatted among 

 the rocks. Their movements are lively, but always 

 at the bottom; they keep in shoals, and deposit 

 their spawn in the month of September, in the 

 clefts of rocks." t The first species we have to 

 describe belongs to the more ordinary form of the 

 genus, with a deep body and large head, but is 

 entirely without the pre-opercular spines. It ap- 

 pears to be the plecostomus represented in Gronovius, 

 tab. iii. figs. 1 and 2, although it differs slightly from 

 that figure in the form of the tail, which has no 

 elongation of the outward rays, and has the lower 

 longer than the upper. We keep it in the mean 

 time as, 



H. PLECOSTOMUS, SPOTTED Hypostoma. — L'Hy- 

 postome plecostome, Valenc. Hist. Nat. des Poissons, 

 XV. p. 489. — Macusi name, Yau-ura. Schomb. 

 Drawings.^ No. QQ. — Mr. Schomburgk's notes in- 

 form us that this fish was found in April in the 

 Rio Branco under the roots of trees, that it was 

 retentive of life, and that the intestines form many 



* Quoted from Valenciennes, xv. p. 513. 



t D'Orbigny, quoted by Valenciennes, 1. xv. p. 497. 



