A REVIEW OF THE SILUROID FISHES OR CATFISHES 



OF JAPAN. 



By David Starr Jordan and Henry W. Fowler, 



Of the Leland Stanford Junior University. 



In the present paper is given a review of the catfishes or JVema- 

 tognath! known to inhabit the waters of Japan. The paper is has^d 

 on the collections made by Messrs. Jordan and Snyder in 1900, 'a 

 series of these specimens being placed in the U. S. National Museum. 



Order NEMATOGNATHI. 

 CATFISHES. 



Parietals and supraoccipital confluent. Four anterior vertebra 

 coossitied, and with ossicula auditus or weberian apparatus. No 

 mesopterygium. Basis cranii and pterotic bone simple; no coronoid 

 bone. Third superior pharyngeal bone wanting, or small and resting 

 on the fourth; second directed backward. One or 2 pairs of basal 

 branchihyals; 2 pairs of branchihyals. Suboperculum wanting, or 

 modified into the uppermost branchiostegal. Mesocoracoid present. 

 Premaxillary forming border of mouth above, except in one famil}" 

 {Di^domystldde)^ in which the maxillaries also bear teeth. Inter- 

 clavicles present. No scales. Skin naked or with bony plates. 



This group comprises 2 families, Plotosidse and Slluridai among 

 Japanese fishes. 



{vfffxa^ thread; yva^oz^ jaw; from the maxillary barbels which are 

 always present.) 



a. Air bladder well developed, usually simple or with transverse constructions, lying 

 free in the abdominal cavity. Mouth terminal, teeth villiform, conical, incisor 

 or molarlike; intestines short, arranged in longitudinal folds; body naked, or 

 with 1 series of lateral plates; diaphragm membranous; tip of scapular process 

 reaching basioccipital. 

 b. Dorsal and anal nearly coextensive with the caudal portion of the vertebral col- 

 umn; the first dorsal short, the second not adipose, united to the caudal; 

 opercle present, 

 c. Gill membranes not confluent with the isthmus, or unite<l only by a very 

 narrow strip; gill-openings broad; 2 dorsals, the first short and with spine 

 in front; second donsal long and joined to caudal; anal united with caudal; 

 no adipose dorsal; ventrals many-rayed; air-bladder not inclosed in l)(>ue. 



PLOTOSID.i:, 1. 



Proceedings U. S. National Museum, Vol. XXVI-No. 1338. 



