500 MEMOIRS OF THE CARNEGIE MUSEUM 



reaching the end of the caudal; caudal broad, rounded; dorsal and anal lobes 

 extending beyond the caudal. 



A conspicuous band from the snout to the end of the first dorsal rays; a 

 prominent ocellus at the base of the upper caudal rays; vertical fins spotted; traces 

 of cross-bands, which are prominent in the very young. 



AcARiCHTHYS gen. nov. 



Type, Acara heckelii Miiller and Troschel. 



Allied to Retroculus, but the dorsal lobe of the first gill-arch very feebly de- 

 veloped, the rakers about two, along its base. Mouth small, the premaxillary not 

 greatly protractile. Caudal emarginatc, scaled at its base only; eye in posterior 

 half of the head. 



This genus bridges the gap between JEquidens on the one side and GeopJiagus 

 on the other. It approaches Mquidens geayi very closely in shape. 



339. Acarichthys heckeli (Miiller and Troschel). 

 Acara heckelii Muller and Troschel, in Schomburgk, Reisen, III, 1848, 624 



(swamps and savannas). — GDnther, Catalogue, IV, 1862, 279. 

 Geophagus ihayeri Steindachner, "Chromiden Amazonenstromes," in SB. Akad. 



Wiss. Wien, LXXXI, 1875, 48, pi. 3, fig. 2 (Teffe; Villa Bella; Obidos; Cuda- 



jas; Tonantins; Jatuarana; Ueranduba; Serpa; RioTapajos; Rio Trombetas; 



Rio Negro; Xingu; Lakes Hyanuary, Jose Assu, Saraca, Alexo, and Maximo). 



— Pellegrin, "Cichhdes," in Mem. Soc. Zool. France, XVI, 1903, 189 (Obidos; 



Manaos; Tonantins). 

 Geophagus (Mesops) thaijeri Pellegrin, Bull. Mus. d'Hist. Nat., VIII, 1902, 182 



(Santarem; Manaos; Teffe; Tonantins; Tabatinga). 

 Acara subocularis Cope, Proc. Am. Philos. Soc, XVII, 1878, 696 (Peruvian 



Amazon) . 



Although the description of heckelii is very brief it is quite evident that it is 

 Geophagus-like; the lateral spot should make it either surinamensis or ihayeri, 

 while the fin formula given by Miiller and Troschel leaves no doubt that they had 

 the present species. 



Three specimens, 95-155 mm. Rupununi. (C. M. Cat. No. 2370a-6; I. U. 

 Cat. No. 12514.) 



Two specimens, 95-100 mm. Rockstone sand-bank. (C. M. Cat. No. 2371a; 

 I. U. Cat. No. 12515.) 



Four specimens, 75-115 mm. Gluck Island. (C. M. Cat. No. 2373a-fo; 

 I. U. Cat. No. 12516.) 



