99. LORICARIA. 259 



terior margin of the orbit with a large notch, so that the diameter 

 of the orbit and notch together is one-fourth, or nearly one-fourth, of 

 the length of the head. The width of the interorbitai space is a little 

 less than the horizontal diameter of the eye. Teeth minute, rudi- 

 mentary/ those of the mandibles twice the number of the inter- 

 maxillary teeth. Labial fold broad and thick, without papillae or 

 fringes. The lower side of the head naked ; scutes of the head rough, 

 the roughnesses being small spines round the margin of the snout ; 

 the median scutes of the nape bicarinate. Thorax with three trans- 

 verse series of small polygonal scutes ; abdomen with 5-6 transverse 

 series, each composed of one median piece and of a larger one on the 

 sides ; the three pieces are sometimes confluent into one broad scute. 

 L. lat. 32. The origin of the dorsal fin is somewhat behind that of 

 the ventrals. The upper caudal ray sometimes much prolonged. 

 Barra do Rio Negro. 



13. Loricaria nudirostris. 

 Kner, Loricar. p. 22. taf. 4. 



Snout rather produced and pointed, the greatest width of the head 

 being five-eighths of its length. Eye of moderate size ; the posterior 

 margin of the orbit with a notch half as large as the eye ; the width 

 of the interorbitai space is somewhat more than the horizontal dia- 

 meter of the eye. Teeth minute, rudimentary, few in number. La- 

 bial fold broad, without fringes. The lower side of the head naked, 

 with a broad band of rough scutes round the margin of the snout. 

 Head rough above, with elevated lines ; scutes of the nape bicarinate. 

 L. lat. 31. Scutes of the thorax and abdomen rather large, regularly 

 arranged in transverse series. The origin of the dorsal fin is a little 

 behind that of the ventrals. Fins with black dots. {Kner.) 



Barra do Bio Negro. 



*** Snout long and narrow. 



14. Loricaria depressa. 

 Hemiodon depressus, Kner, Loricar. p. 27. taf. 7. fig. 1. 



Snout long and narrow, with its extremity slightly turned upwards ; 

 the head is three-fifths as broad as long, and its length is contained 

 thrice and a fourth or thxice and a third in the total (without caudal). 

 Eye of moderate size, its diameter being equal to the width of the 

 interorbitai space ; orbit with a shallow notch behind. Teeth absent 

 in the upper jaw, minute and rudimentary in the lower. Fold of 

 the lower lip well developed, smooth ; the lower side of the snout 

 shielded, the vicinity of the mouth being naked. Scutes of the head 

 and nape smooth ; nape with a shallow median groove to the dorsal 

 fin. The lower side of the thorax is covered with very small, the 

 abdomen with larger irregular scutes. L. lat. 27. The origin of 

 the dorsal fin is opposite to that of the ventrals ; the upper caudal 

 ray prolonged. (Kner.) 



Rio Negro and Marabitanns. 



s 2 



