182 



Mr. C. T. Regan on the Siluroid Genera 



XIII. — A Synopsis of the Species of the Sihirid Genera 

 Parexostonia,Cliimanliichtli}-sarif?Exostoma. By C. Tate 

 Eegan, B.A. 



The fishes whicli liave usually been placed in the genus 

 Exostcvia of Blyth fall into three very distinct groups, Avliich 

 should be regarded as genera, as will be aj)parent from the 

 following synopsis : — 



I. Teeth all pointed, those of the upper jaw 

 forming a band, wliich is produced back- 

 wards at the sides ; gill-openings ex- 

 tending on to the lower surface of the 

 body ; fuld of the lower lip broadly inter- 

 rupted ; pectoral Avith 11 branched rays . . 

 Pectoral extending f-f of tlie distance from its 

 base to the base of ventral ; caudal peduncle 



3 times as long as deep 



Pectoral extending l-'l of the distance from its 

 base to the base of ventral ; caudal peduncle 

 twice as long as deep 



[gen. nov. 

 Paeexostoma, 



1. p. Sfoh'czlce, Day. 



[Regan. 



2. P. mcicuhdum, 



II. Teeth all pointed, those of the upper jaw 



forming a band which is not produced 



backwards at the sides; gill-openings not 



extending on to tlie lower surface of the 



body ; fold of the lower lip continuous or [Sauv. 



not'; pectoral with 13-19 branched r.ays . . CHraARRnicHTHvs, 



A. Lower angle of gill-opening below tlie middle of the ba-'e of 



pectoral, which fin extends about to the base of ventral ; fold of 

 the lower lip not continuous. 

 Pectoral with 13 or 14 branched rays ; caudal 



peduncle much longer than deep 1. C. Duvidi, Sauv. 



Pectoral with 16 or 17 branched rays; caudal 



peduncle about as long as deep 2. C. BJythit, Day. 



B. Lower angle of gill-opening opposite the middle of the base of 



pectoral. 



Pectoral with 14 or 15 branched rays, not reach- 

 ing the ventral ; fold of the luwer lip nut 

 continuous 3. C. Fece, A'incig. 



Pectoral with 19 branched rays, 'extending be- 



Yond the base of the ventral; fold of the [Vincig. 



lower lip continuous 4. C. macyoptenis, 



III. Each jaw with 2 bands or patches of 



small pointed teeth, with an enlarged outer 

 series of compressed obtuse teeth ; gill- 

 openings not extending on to the lower 

 surface of the bijdy ; fold of the lower lip 

 continuous; pectoral with 10-12 branched 

 rays Exostoma, Blyth. 



