93. I'LECOSTOMUS. 235 



9. Plecostomus wnchereri. 

 D. 1/7. A. 5. P. 1/0. V. 1/5. L. lat. 26. 



Head and nape depressed, scarcely elevated along the middle, its 

 length being contained thrice and two-thirds in the total (without 

 caudal). No ridge between the eye and the nostril. The diameter 

 of the eye is one-third of the width of the interorbital space. The 

 middle of the extremity of the snout is naked. Labial folds well 

 developed, with numerous papillae ; barbel short, as long as the eye. 

 Upper jaw "nath about forty-five teeth on each side, the lower with 

 about thirty-six. Interoperculum without any spines. A triangular 

 space on each side of the lower surface of the head, between the 

 labial fold and the gill-opening, is covered with minute shields, the 

 interspace behind the middle of the lower lip being naked. Thorax 

 and a large triangular blotch, extending in the middle of the belly 

 to between the ventral fins, covered with minute rough shields, 

 the lateral portions of the belly being naked. The length of the 

 base of the dorsal is more than its distance from the second fin ; 

 there are six or seven scutes between the two fins. Dorsal fin not 

 mvich higher than long, the length of its first ray being less than 

 that of the head. Caudal fin obliquely subtnineated ; its outer rays 

 are not spiny, and the lower is only a little longer than the upper ; 

 there are thirteen or fourteen scutes between the anal and caudal. 

 Pectoral spine very strong, armed above with numerous long curved 

 spines ; it extends backwards to, or nearly to, the middle of the ven- 

 tral fin. The scutes of the body are striated, but not keeled, and the 

 posthumeral ridge is rather obtuse. Body and all the fins with nu- 

 merous round brown spots, which are not much smaller than the 

 eye, forming two series between the dorsal rays, and one between 

 the caudal rays. 



Brazil. 



a. Fine specimen. Bahia. From Dr. 0. Wucherer's Collection. 

 b-c. Adult : stufi'ed : 1 3 inches long. Pm-chased of Mr. Argent. 

 (/. Half-grown. From the Collection of the Zoological Society. 



10. Plecostomus brevicauda. 

 D. 1/7. A. 5. P. 1/6. V. 1/5. L. lat. 2Q. 

 Head and nape depressed, scarcely elevated along the middle ; its 

 length is two-sevenths of the total (without caudal). No ridge be- 

 tween the eye and the nostril. The diameter of the eye is nearly 

 one-third of the width of the interorbital space. The middle of the 

 extremity of the snout is naked. Labial folds well developed, with 

 numerous papilla; ; barbel short, longer than the eye. There are 

 about forty teeth on each side of the upper and lower jaws. Inter- 

 operculura without any spines. A triangular space on each side of 

 the lower surface of the head, between the labial fold and the giU- 

 opening, the thorax, and almost the entire abdomen before the ven- 

 trals arc covered with minute rough shields. Tlie length of the base 

 of the dorsal fin equals its distance from the caudal ; there are seven 



