532 PROCEEDINGS OF THE ACADEMY OF [July, 



ee. Anal spines 6. Dorsal spines 15 or 16. Preorbital less than 

 orbit in width. Scales on cheek in 3 or 4 series. Soft dorsal 

 and anal scaled, 2. Ch^tobranchopsis. 



dd. Gill-rakers stiff, lanceolate, crenulate on inner margin. Perciform. 

 Scales small. Spinous and soft dorsals of nearly eciiial extent, 

 and separated by a notch. Anal spines 3. Each jaw with a 

 broad band of villiform teeth. Dorsal and anal fins scaled, 



3. CiCHLA. 



cc. Gill-rakers short and few. 

 /. Vertical limb of preopercle entire. 



g. Scales of the lateral line much longer than the others. About 2 

 transverse series of scales in the anterior part to each scale of 

 the lateral line. First series of teeth incisors, separated from 

 the rest by a moderate space, 4. Uaru. 



gg. Scales of the lateral line not larger than the others. 



[h. A series of incisors, a band of villiform teeth behind them. Anal 



with 8 spines, 5. Neotroplus. 



hh. Teeth all conical, the front series remote or not. 



i. Premaxillary very greatly protractile. 



j. Anal spines 3. 



k. Lateral line not overlapping. Snout equal to postorbital portion 

 of head. Mouth oblique, preor])ital narrow (^ orbit). Nos- 

 trils nearer tip of snout than eye, ..... 6. Acaropsis. 

 kk. Lateral line with the upper and lower limbs overlapping. Snout 

 much produced, more than twice the length of postorbital por- 

 tion of head. Preorbital very large, nearly twice as wide as the 

 eye. Nostrils much nearer orbit than tip of snout. Mouth 

 low, nearly horizontal. Premaxillary an orbital diameter below 

 the eye. Caudal densely scaled. Maxillary reaching to nos- 

 trils, 7. Retroculus. 



jj. Anal spines 6. Snout not greater than postorbital portion of head. 

 Preorbital narrow. Mouth oblique, premaxillary on level of 

 lower third of eye, more protractile than in the other genera. 

 Maxillary reaching to front margin of eye. The origin of the 

 ventral falls vertically below that of dorsal, . . 8. Petenia. 

 a. Premaxillary comparatively little protractile. 



I. Ventrals inserted behind origin of dorsal. 



m. Cheeks scaled. 



n. Jaws subequal. 



0. Anal spines 3. 



p. Soft portions of vertical fins densely scaled to near the tip ; dividing 



line between fins and liody indistinct. About 6 of the anterior 



teeth of lower jaw enlarged canines, ... 9. Astronotus. 



pp. Soft portions of dorsal and anal naked or scaled on base only. 



Caudal scaled at its basal half. liOwer jaw without enlarged 



canines, 10. ^quidens. 



00. Anal spines more than 3, some of the teeth usually enlarged, often 

 canine-like. 



q. Lower lip with a frenum, its folds interrupted mesially, 



11. Cichlosoma. 



