93. PLECOSTOMUS. 237 



12. Plecostomus granosus. 

 Cuv. Sf Val. xv. p. 502. 



D. 8. A. 7*. P. 1/7*. 



Interoperculum without spines. Head and body depressed, with- 

 out keels or ridges. Lips with coarse soft granulations; a large 

 space before the ventrals is occupied by osseous scutes, so that only 

 the anterior half of the abdomen, and the praeanal region are naked. 

 The eyes are small, placed between the second and third thirds of 

 the length of the head, which is one-fourth of the total (with the 

 caudal). Brownish. (Val.) 



Cayenne ; Brazil. 



•* Margin of the snout with short bristles. 



13. Plecostomus barbatus. 



Cuv. $■ Val. xv. p. 606 ; Ktier, Hypostom. p. 268. taf. 2. fig. 2. 

 D.l/7. A. 5-6. P. 1/6. L. lat. 24-25. 



Head much depressed, with the occiput and nape very little con- 

 vex ; its length is contained thrice and a third in the total (without 

 caudal) ; the diameter of the eye is one-half of the width of the 

 interorbital space. The margin of the snout from its extremity to the 

 gill-opening is soft, and covered with very small prickles, which 

 become a little longer backwards ; the operculum also has a finely 

 serrated margin f. The lower side of the head, thorax, and belly 

 entirely naked. Dorsal fin not higher than long in old examples, 

 but rather higher in immature specimens ; the anterior rays always 

 shorter than the head ; the length of the base of the dorsal fin is 

 nearly equal to its distance from the caudal ; there are six or seven 

 scutes between the two dorsal fins. Caudal fin obliquely truncated, 

 the lower rays being considerably longer than the upper. The pec- 

 toral spine is broad, extending nearly to the middle of the ventral, 

 and is covered above with short curved spines. Twelve scutes be- 

 tween anal and caudal : scutes of the body finely granulated and 

 striated, without keels ; posthumeral ridge very obtuse. Uniform 

 dark brown. 



Surinam. 



a. Fine specimen, 9 inches long. Surinam. Purchased of Mr. 



Kappler. 



b, c. Half-grown and young. 



14. Plecostomus gnttatus. 

 Cuv. fy Val. xv. p. 508. 

 Very similar to P. barbatus, but with conspicuously smaller eyes. 



D. 1/7. A. 6. P. 1/6. L. lat. 25. 

 Head much depressed, with the occiput and the nape flattish ; its 



* These numbers are so unusual in this genus, that we may well suspect them 

 to be erroneous. 



t This species evidently approaches the group with erectile interopercular 

 spines. 



