100 CALIFORNIA ACADEMY OF SCIENCES. 



qq. Head longer than broad; inner surface of gill-cover usually 

 with one or more dermal pouches. 



r. D. I, 9-10. Teeth on the vomer in two transversely ovate 



patches, which are sometimes united — always remote from 



the small palatine patches. Sciades xxviii. 



rr. D. I, 6-8. 



s. Caudal long and lanceolate, the middle rays more than J of 



the length; adipose fin long and low, joined to the caudal. 



D. 8. No evident occipital process. Dorsal placed over the- 



ventrals. Nemuroglanis xxix. 



ss. Caudal forked or rounded. 



t. Inner teeth of the upper jaw slender and freely movable, 

 the band scarcely narrowed in the middle; teeth of vomer 

 and palatines much smaller, (the palatine teeth smaller 

 than those on the vomer), villiform. Adipose fin equal 

 to or longer than the anal fin; caudal deeply forked, the 

 lobes pointed. Brachyplatystoma xxx.. 



tt. Teeth all similar in the upper jaw and on the vomer. 

 M. Head narrowed forward, its width at the mouth 

 scarcely if any more than two-thirds its greatest width; 

 adipose fin longer than the anal fin. 

 V. Upper jaw little longer than the lower. Caudal rays 

 normal. Intermaxillarj^ band of teeth not or scarcely 

 narrowed in the middle. Dorsal sjoine equidistant 

 from snout and middle of adipose fin. 

 IV. Palatine patches of teeth present biit very remote 

 from the vomerine patches; vomerine patches sep- 

 arate in young, united in adult specimens, forming 

 a /\-shaped patch. Caudal deeply forked, the lobes 

 long and pointed. Duopalatinus xxxi. 



imo. Palatine teeth present, joined to the vomerine 

 patches, together forming a shallow band immedi- 

 ately behind the intermaxillary band of teeth. 

 (Gen. ? One species, lutkeni, not seen.) xxxii. 

 wiow. Palatine teeth none; vomerine teeth in twa 

 transverse ovate patches which are sometimes, 

 united; intermaxillary band not narrowed in the 

 middle. Caudal broadly rounded, or deeply emar- 

 ginate. Steindachneria xxxiii. 



vv. Lower jaw produced bej'ond upper. Intermaxillary 

 band of teeth much narrowed in the middle. Vomer- 

 ine teeth in a single patch, much wider than the 

 intermaxillary baud; palatine patches closely con- 

 tiguous to the vomerine patch. 



Hemisorubim xxxiv^ 



