FISHES. 
325 
Genus 3—COREGONUS. —Artedi. 
Generic Character .—Head compressed ; mouth situated at the 
point of the snout; teeth yery minute; palate, tongue, and 
lower jaw frequently devoid of them ; scales large; two dorsal 
fins, the second one adipose and destitute of rays; branchial 
membrane with seven or eight rays. 
Genus 4.—ARGENTIN A .—Linnceus. 
Generic Character. — Mouth small, depressed; tongue pro¬ 
vided with hooked teeth, and a transverse row of smaller ones 
on the vomer; branchial membrane with six rays. 
Genus 5. —CURIMATA— Cuvier. 
Generic Character. —Head depressed; mouth small, placed at 
the extremity of the snout; teeth various; first dorsal fin above 
the ventrals, the second adipose and destitute of rays; four rays 
on the branchial membrane. 
Genus 6.—ANASTOMUS.— Cuvier. 
Generic Character. —Head compressed; mouth small, ter¬ 
minal; a single row of small teeth above and below; the lower 
jaw turned up in front of the upper one; branchial membrane 
with four rays 
Genus 7. — SERRASALM US— Lacepede. 
Generic Character. —Teeth triangular, edged, dentated, and 
arranged in a single row in the intermaxillaries and lower jaw ; 
branchial membrane with four rays; body compressed ; back 
high ; venter produced. 
Serrasalmus rhombeus. —The Rhombic Salmon. 
Plate LXXVIII. fig-. 7. 
Dull-red above, with some irregular dusky spots ; sides and 
abdomen silvery-white, the latter carinated and serrated; tail 
luniform, with a black fillet at its edge ; a three-spiked spine 
placed before the dorsal fin. Inhabits the rivers of Surinam. 
Genus 8. - PIA B U C U S.— Cuvier. 
Generic Character. —Head small; mouth with a small open- 
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