SOUTH AMERICAN NEMATOGNATHI. 235 



Acanthodoras cataphractus Bleeker, Nederl. Tijd. Dierkunde, i, 16, 



1863; id. Silures de Suriname, 40, 1864 (Surinam). 

 Cataphractus americanus Bloch & Schneider, "Syst. Ichthyol. 107, 



pi. 28," 1801; Lacepede, Hist. Nat. Poiss. v, 124 and 127, 1803 



(Carolina?). 

 Doras blochii Citv. & Val. Hist. Nat. Poiss. xv, 277, 1840 (copied). 

 ?Doras brunnescens Schomburgk, Fish. Guiana, jiart i, 163, 1841 



(Upper Essequibo). 

 Doras polyramma & poh/ijramma Heckel MS. Kner, 1. c. 126 and 



127. 

 Callichthys aspe.r Gronow, "Cat. Fish. ed. Gray, 157, 1854." 

 Habitat: Central Brazil; Giiiana. 



174. Doras spinosissimus. 



Doras spinosissimus Eigenm. & Eigenm. Proc. Cal. Acad. Sci. 2d 

 Ser. i, 161, 1888 (Coary). 



Short and thick, the width below the dorsal spine 

 greater than the depth; caudal peduncle little deeper 

 than wide. Head as broad as long, its depth 1^^ in its 

 length; top of head, opercle, preopercle and suborbitals 

 finely granular; the nasal bones with their free margin 

 spinous. Top of head broad and flattish. Dorsal plate 

 broad, without prominent downward or backward pro- 

 cesses. Sutures of the skull marked by smooth lines. 

 Fontanel reduced to a small oval opening surrounded by 

 granulations. 



Eye If in the snout, 7 in the head, 3 in the inter- 

 orbital. 



Maxillary and postmental barbels reaching to the pec- 

 toral pore; mental barbels f as long as the postmentals. 



Snout broad, its width at the rictus 1| in the head. 

 Jaws subequal; teeth minutely villiform, the intermax- 

 illary band 6 times as wide as deep. 



Gill-opening continued forward to below the upper 

 angle of the preopercle. Humeral process not reaching 

 the tip of the pectoral spine by about an orbital diame- 

 ter, its surface with short sharp spines, a series of which 

 near the lower margin is enlarged. 



Lateral scutes very high, covering almost the entire 



