38 TELEOSTEI : NEMATOGNATHI. — XI. 
Famity XXIV. SILURIDAL. (THE CAT-FISHEs.) 
Body more or less elongate, naked or with bony plates; margin 
of upper jaw formed by premaxillaries only, the rudimentary 
maxillaries forming the base of a long barbel; teeth in villiform 
bands. Dorsal fin usually present, short, above or before ventrals ; 
usually an adipose fin behind dorsal. First ray of dorsal and pec- 
torals usually developed as a stout spine. Lower pharyngeals 
separate. Air-bladder present, large. A vast family of more 
than 100 genera and 900 species, mostly of the rivers and swamps 
of warm regions, especially of South America and Africa. A few 
species are marine. Many of them are excellent as food, and all 
are very tenacious of life. 
a. Dorsal short, placed before ventrals; adipose fin present; gill membranes 
more or less free from isthmus; body naked. 
6. Anterior and posterior nostrils close together, neither with a barbel, the 
posterior with a valve; palatines with teeth; caudal forked. Marine 
species. (Tachysurine.) 
c. Lower jaw with 2 barbels; maxillary barbel band-like; dorsal and 
pectoral spines ending in striated filaments. . AILURICHTHYS, 34. 
cc. Lower jaw with 4 barbels; spines not filamentous. TACHYSURUS, 35. 
bb. Anterior and posterior nostrils well separated, the posterior with a 
barbel; barbels 8; teeth in jaws only. (Jctalurine.) 
d. Adipose fin with its posterior margin free. 
é. Premaxillary band of teeth, without backward processes. 
J. Supraoccipital bone prolonged backward so that its emarginate 
apex fits closely around the anterior point of the second inter- 
spinal, thus forming a continuous bony bridge extending from 
the head to the dorsal spine. sad species ; C. deeply 
forked.) \geane ee » i » , J@PALURUA, SG. 
Sf. Supraoccipital bone Ae reaching se ee interspinal, the bony 
bridge more or less interrupted. 
g. Eyesnormal. .. é.(ipa epee. 2.) AMERIDRUS, re 
gg. Eyes concealed by me sien a sete) On) iio ee ONE A eee 
ee. Premaxillary band of teeth, with a lateral backward process on 
each side; lower jaw prominent. . . . . . . LEprops, 39. 
dd. Adipose fin keel-like, adnate to the back, more or less joined to 
caudal fin; a (venom) pore in axil of pectoral... Norurus, 40. 
34. AILURICHTHYS Baird & Girard. (aidoupos, cat; 
ix6us, fish.) 
48. A.marinus (Mitchill). Garr-Topsam. Sea Cat. Dusky 
bluish. Head short and broad. Maxillary barbels reaching end 
of P. spine; P. filament reaching vent, D. filament to adipose fin ; 
upper lobe of C. longer; palatine teeth in a nearly continuous 
band. Head 44. D.I.7. A. 23 L. 30 in.- N. Y. to Texas, 
common S8., not entering streams. 
