siLUEiD^.— ex. 327 



between the intermaxillaries and the eyes; the anterior 

 ire suboval or subcircular, and the posterior linear, with 

 I raised margin, from the front of which the upper bar- 

 bels originate; the eyes are generally placed in the 

 interior half of the head; the dorsal and pectoral fins 

 ire each provided with a stout, pungent spine. The adi- 

 pose fin is developed, not rayed, and the rays of the 

 iorsal fin are few in number. The branchial apertures 

 ire ample, continued from the supero-posterior angles 

 3f the opercula to beneath the throat. The air-bladder 

 is well developed. The species commonly inhabit deep 

 or sluggish waters, and are very tenacious of life — 

 Bspecially those_pf Amiurus. 



* Adipose fln with its posterior margin free, not comiected with 

 the caudal flu. 

 t Intermaxillary band of teeth convex in front, abruptly trun- 

 cate behind, without lateral backward processes ; branchi- 

 ostegals 8 or 9 (rarely 10 or 11) ; ventral fins normally with 

 8 rays. 



X Supraoccipital bone prolonged backward, its apex emar- 



ginate, receiving the pointed anterior end of the second 



interspinal, thus forming a continuous bony bridge from 



the snout to the base of the dorsal ; branchiostegals 8 or 



9; head elongate; mouth small, terminal, the upper jaw 



the longer; anal fln elongate, of 24 to 34 rays; caudal 



fln furcate ; body elongate, more or less slender, silvery, 



covered with thin skin. . . IcHTH^Lnaus, 1. 



%% Supraoccipital bone free behind, not connected with 



the interspinal ; branchiostegals normally 9 (varying 



from 8 to 11) ; head broad ; mouth broad, terminal ; 



anal fln moderate or rather long, with 15 to 37 rays ; 



caudal fln usually truncate, but often more or less 



deeply emarginate or even forked; body usually 



more or less shortened, covered with a rather thick 



skin AinxTRUS, 2. 



ft Intermaxillary band of teeth convex in front, with a lateral 

 backward extension on each side; branchiostegals not' 



