Zoological Society. 391 



Though founded upon a single individual, this appears a truly di- 

 stinct species in the above characters from B. Raii, BL, of which it 

 presents the general appearance, colour and habit. The example 

 seen measured eighteen inches and a quarter in length, and was eight 

 inches deep at the origin of the dorsal and anal fins. As settling, by 

 its partially aculeate scales, the true position of Taractes, this fish 

 has been a very valuable acquisition. 



Gen. Taractes, nob. 



Char. Gen. — Corpus ovatum compressum (ad finem pinnae dorsalis 

 analisque abrupte in caudam contractum), squamis cycloideis 

 retrorsum aculeato-umbonatis muricato-asperum. Caput squa- 

 mosum ; oculis magnis ; rostro brevissimo simo ; rictu magno sub- 

 verticali ; dentibus Bramee similibus subscobinatis recurvis, exter- 

 nis raajoribus ; palatinis vomereque armatis. Operculum simiplex 

 inerme. Prceoperculum basi eximie dentato s. subcalcarato ; sub- 

 operculo interoperculoque denticulatis. 



Pinnee malacopterygise, s. omnes radiis moUibus. Ventrales subju- 

 gulares. Pinna dorsalis analisque unica conformis lata : caudalis 

 simplex integra rotundata. Membrana hranchiostega septem-ra- 

 diata. 



SquamcK magnae trapeziformes postice emarginatse cycloideae ; um- 

 bone in aculeum recurvato-erectum producto. 



Taractes asper. 

 D. 5 + 28; A. 3 + 20; P. 17; V. 1 + 5 ; C. ^^^'j M. B. 7 ; 



Squamae corporis in serie longitudinali 43 fere. 



The generic name imposed at its first discovery on this particularly 

 interesting, though plain and sober- coloured little fish, expresses the 

 difliculty experienced in settling its relations of affinity, which are 

 indeed so obscure and complicated, that but for the subsequent dis- 

 covery of Brama longipinnis, with its similarly, though contrariwise, 

 hooked scales, its true position, next to Brama, with analogies to 

 many other families (e. g. Zenida, Caproidce, Scombridce), must have 

 remained in abeyance. 



Pteraclis Papilio. p. longitudine altitudinem plus quater multi- 

 plicatam cequante : pinna dorsali prima anulique cceruleo-violaceis, 

 lituris inter radios aureo-viridibus postice biseriatis ; hac radio 

 secundo, ilia quarto validiore, ceteris capillaceis jlexuosis. 



V"^^ D. 35 ; 2^^ D. 6 ; A. 35 ; P. 18 ; V. 6 ; C. |^j^^^*. 



Nothing can exceed the splendour of the deep violet-blue, with 

 the gold and green iridescent dashes or short stripes between the 

 rays of the first dorsal and the anal fins. It resembles the breast of 

 certain Humming-birds, and contrasts singularly with the pure uni- 

 form silvery whiteness of the whole head and body. The second 

 dorsal fin, though very small, is sufficiently distinct in this species, 

 and possibly has been merely overlooked or mistaken in imperfectly 

 preserved specimens of others for an accidentally detached portion 

 of the first dorsal fin. The proportions, not only of the depth, but 



