South- American Cichlid Genus Acaropsis. 34:5 



lower part of anterior arch. Scales 23-24 -^-^, ^ a scale 

 between upper lateral Hue aud dorsal fiu for most ot" its 

 length. Dorsal XVI 8, eomniencin;^ above tiie opercular 

 cleft, the spines subequal or slij^htly increasing after the 

 sixth, the lust nearly ^ the length of head; soft fin extending 

 beyond middle of caudal. Anal III 8. Pectoral as long as 

 the head; ventral extending to origin of anal. Caudal 

 rounded or pointed, the middle rays being somewhat pro- 

 dnced. Caudal peduncle ^ as long as deep. Brownish, with 

 a dark longitudinal stripe from eye to base of caudal and a 

 dark obliipie stripe from eye to angle of prseoperculum; soft 

 dorsal, anal, and caudal obscurely spotted. 

 R. Essequibo. 



1-2. (55 and 57 mm.) types of the species. R. Essequibo. Mr. Ehrliaivlt. 



This curious species was considered by Pellegriu to 

 hi probably identical with Blotoduina Ajassizii, Stdr. 

 However, there is no trace of a lobe on the upper part of 

 the anterior branchial arch, and the scaly pmeoperculum also 

 separates it from the known species of Biotodorna. 



Acaropsis. 



Acara (part.), Heck, Anu. Mus. Wien, ii. 1840, p. S38 ; Giinth. Cat. 



Fish. iv. p. 270 (1862). 

 Acaropsis, Steind. Sitzb. Ak. Wien, Ixxi. 1875, p. 80 ; Eif^enra. & Bray, 



Aun. Ac. N. York, vii. 1894, p. 613; Pellegr. M6ui. Soc. Zool. 



France, xvi. 1003, p. 180 (1904> 



Differs from Acara only in the somewhat larger mouth, 

 very protractile preemaxillaries, and exposed maxillary. 



A single species from the Amazon, Venezuela, and Guiana. 



The skeleton is v( ry similar to that of Acara tetramerus, 

 but the greater length of the ascending processes of the 

 prsemaxillaries, which extend to above the middle of the orbit, 

 is correlated with a somewhat shorter occipital crest and 

 shorter and weaker parietal crests. There are 25 vertebrae 

 (12 + 13), the third bearing a pair of feeble inferior 

 apophyses. 



Acaropsis nassa. 



Acara nassa, Heck. Ann. Mus. Wien, ii. 1840, p. 353 ; Giinth. Cat. 



Fish. iv. p. 281 (1862). 

 Acara coi/natus, Heck. t. c. p. 356. 

 Acara unicolor, Heck. t. c. p. 357. 

 Acara {Acaropsis) nassa, Steind. Sitzb. Ak. AVien, Ixxi. 1875, p. 81, 



pi. ii. 

 Acaropsis nassa, Eigenm. & Bray, Ann. Ac. X. York, vii. 1894, p. 613 ; 



Pellegr. Mem. Soc. Zool. France, xvi. l'J03, p. 180 (1004). 



Ann. (i; Mag. N. Hist. Ser. 7. Vol. \v. 2J: 



