NO. 133.S. JAPANESE CA TFISHES-.TORDAN AND FO WLER. 901 



/. Adipose fin not adnate, free behind, as in Amemrm; mental barbels as 

 usual, the median pair not notably distant. 

 g. Anal rays 20 to 25. 



/;. Caudal fin deeply forked; upper surface f.f head bony and {rranu- 



lated, the skin covering the bones being very thin. . Fluridraco, 4. 



hh. Caudal fin subtruncate; upper surface of head covered with thick 



smooth skin, concealing the bones Pscii(Iol»igriis, 5. 



gg. Anal rays 14 to 17; eyes very small; head covennl with soft skin; 



caudal deeply forked Leiocassis 6. 



.//. Adipose fin adnate to the back and connected with tlie caudal; caudal 

 rounded; median mental barbals far apart; body elongate; head 

 small, smooth above; dorsal well forward Liohagrus, 7. 



2. TACHYSURUS Lacepede. 



Tachgsunis Lacepede, Hist. Nat. Poiss., 1803, p. 151, pi. v, fig. 2 {Sinemb). 

 Arius(f CuviER and Valenciennes, Hist. Nat. Poiss., XV, 1840, p. 52, in part, 



not the "chef de file" or type {graiidicassis, arius, etc.; restricted to Pinte- 



lodus arius by Bleeker in 1858 = Tachysurus) . 

 Ariodes Muller and Troschel, Horre Ichthyol., Ill, 1849, p. 9 [arenanm, etc.) 



{^=Tachiisuvus). 

 Pseiidariiis Bleeker, Ichth. Archipel. Indi. Prodrom. Siluroid., 185S, p. 91 



{Pimelodiis arius; grandicassis being regarded as type of Arius.) 



Body more or less elongate, subterete. Head armed with a bony- 

 shield above, behind which projects an occipital shield, another smaller 

 crescent-shaped shield at the base of the dorsal spine, these processes 

 and bones exposed or covered with very thin skin, and the bones on 

 top of the head together with the occipital process granular; skull 

 with a fontanelle; eyes with a more or less free orbital margin; mouth 

 not large, the upper jaw the longer; teeth in jaws villiform, more or 

 less granular, in a band in each jaw; palatine patches of teeth granu- 

 lar, without a backward projecting angle on the inner margin, and 

 never movable; barbels (3 (no nasal barbels), close together, the poste- 

 rior with a valve; maxillary barbels usually short and terete or some- 

 what compressed. Gill membranes not forming a free margin across 

 the isthmus. Skin smooth, naked, except on the head above. Dorsal 

 fin short, in front of ventrals with a pungent spine: adipose tin well 

 developed, posteriorly free; caudal tin deeply forked; anal tin short: 

 pectorals each with a spine; ventral rays six. General color brown 

 with blue reflections. 



Marine cattishes. The species abundant on sandy shores in the 

 tropical seas, never about coral reefs. None of them occur in Japan 

 proper. 



{raxvs, swift; ovpa, tail.) 



c The generic name Arius may, however, properly be retained for Arius gramiicams, 

 Valenciennes's "chef de file" or type, thus replacing Netuma, although tlu' name 

 Arius is derived from an Indian name Ari. 



