CAT-FISHES. 565 



II. SiLUKiD.E HeteropteEyE. — The rayed dorsal Jin is 

 very little developed, and, if it is present, it belongs to the 

 abdominal portimi of the vertebral eolwinn ; the adipose fin is 

 exceedingly small or absent. The extent of the anal is not 

 mueh inferior to that of the caudal vertebral column. The 

 gill-membranes overlap the isthmus, remaining more or less 

 separate: SiLURlNA. 



SaccobraNCHUS. — Adipose fin none ; dorsal very short, 

 without pungent spine, placed above the ventrals. Cleft of the 

 mouth transverse, anterior, of moderate width ; barbels eight. 

 Eyes rather small. The upper and lateral parts of the head 

 osseous or covered with a very thin skin. Gill-cavity with an 

 accessory posterior sac, extending backwards between the muscles 

 along each side of the abdominal and caudal portions of the 

 vertebral column. Ventrals six-rayed. 



Small fishes from East Indian rivers ; four species are 

 known. The lung-like extension of the branchial cavity 

 receives water, and is surrounded by contractile transverse 

 muscular fibres by which the water is expelled at intervals. 

 The vessels of the sac take their origin in the last branchial 

 artery, and pass into the aorta. 



SiLURUS. — No adipose fin ; one very short dorsal, without 

 pungent spine. Barbels four or six, one to each maxillary, and 

 one or two to each mandible. Nostrils remote from each other. 

 Head and body covered with soft skin. The eye is situated 

 above the level of the angle of the mouth. The dorsal fin is 

 anterior to the ventrals which are composed of more than eight 

 rays. Caudal rounded. 



This genus, of which five species are known, inhabits 

 the temperate parts of Europe and Asia. The species which 

 has given the name to the whole family, is the " Wels " of 

 the Germans, Silurus glanis. It is found in the fresh waters 

 east of the Ehine, and is, besides the Sturgeons, the largest 

 of European Freshwater-fishes, and the only species of this 

 family which occurs in Europe. Barbels six. It attains to 



