THE ANNALS AND MAGAZINE OF NATUEAL HISTOFtY. [SEVENTH SERIES.] No. 88. APHIL 1905. XLIT. — A Revision of the Fishes of the South-American Cichlid Genera Acara, Nannacara, Acaropsis^ and Astrouotus. By C. Tate Regan, B.A. The Cichlidee have recently been monographed by Pellegrin (Mem. Soc. Zooh France, xvi. 1904), who has dealt in a most interesting manner and at considerable length with their anatomy and with the biological problems which they present. However, I have arrived at somewhat different conclusions as to the distinction and arrangement of species in certain genera, which must be my excuse for the present paper. The genera here dealt with are distinguished from other American Cichlidae by the following combination of cha-racters : — Dorsal fin without notch between spinous and soft portions ; gill-rakers short, in small or moderate number ; anal hn with 3 spines ; teeth conical; prseoperculum entire; no lobe on the anterior branchial arch. Their relations to each other may be shown thus : — I. Soft vertical fins scaleless or scaly at the base onlv. D. XIII-XVI 7-12; A. Ill G-11. A. Maxillary not exposed ; pra2maxillaries moderately protractile. Upper lateral line well separated froni dorsiil fin Acarci. Upper lateral line separated from dorsal fin by only \ a series of scales for most of its leng;th Xannacara. B. Maxillary exposed ; prseniaxillaries very protractile. Acaropsis. II. Soft vertical fins covered with small scales; D. XII-XIV 19-21; A. Ill 15-16 Astronotus. Ann. & Mag. N. Hist. Ser. 7. Vol. xv. 23
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