SILURID.E. 



11 



Sixth Subfamily. 

 SILURID.E PROTEROPODES. 



The rayed dorsal fin is always present, and rather short ; ven- 

 trals below or in ft-ont of the dorsal. GUI-membranes confluent 

 with the skin of the isthmus. Vent before, or not much behind, 

 the middle of the length of the body. 



Group N. Hypostomatina. 

 Anterior and j3osterior nostiils close together, generally with a flap 

 between them. Lower lip reverted and dilated. 



a. Head and body entirely covered with soft skin ; maxillary barbels only : 



South American. 



Adipose iin low, elongate 88. Auges, p. 222. 



Adipose fin short, with a moveable spine... 89. Stygogenes, p. 223. 



Adipose fin none, ventrals present 90. Bro.vtes, p. 224. 



Adipose and ventral fins absent 91. Astroblepus, p. 224. 



b. Body completely cuirasscd : South American. 

 * Two barbels at each angle of the mouth. 



Adipose fin short, with a moveable spine . . . 92. Callichtuys, p. 225. 



** Body with four or Jive lo7igitudinal series of scutes on each side ; tail 

 rounded or compressed. 

 Adipose fin present, with a short spine ; eight dorsal rays ; interopercuhuu with- 

 out erectile armature 93. Plecostomhs, p. 230. 



Adipose fin present, with a short spine ; from 13-14 dorsal rays ; interopereulum 



without armature 94. Liposarcus, p. 238. 



Adipose fin present, with a short spine; from 8-10 dorsal rays; interopereulum 

 with erectile spines 95. Ch.etostomus, p. 240. 



Adipose fin present, with a short spine ; from 12-14 dorsal rays ; interopereulum 



with erectile spines 96. Pterygoplichthys, p. 251. 



Adipose fin none ; interopereulum without armature. 



97. Ehinelepis, p. 252. 

 Adipose fin none ; interopereulum with erectile spines. 



98. AcANTiiicus, p. 253. 



*** Tail lony and depressed. 



Snout produced and spatulate 99. Loricaria, p. 254. 



Snout very long and narrow 100. Acestea, p. 260. 



c. Head partly osseous and rough ; body naked or with bony plates on the back : 



East Indian. 



No adipose fin 101. Sisor, p. 262. 



Adipose fin present 102. Erethistes, p. 263. 



d. Head and body covered with skin ; a pair of nasal barbels : East Indian. 

 A plaited adhesive apparatus between tlic pectorals. 



103. Pseudecueneis, p. 204. 

 Lower lip very broad, reflected 104. E.xo.'-to.ma, p. 264. 



