276 CHROMIDEi?. 



narrowci' than the orbit. Interorhital space rather flat, wider than 

 the orbit. Operciilnm scaly, terminating in a prominent, rounded, 

 stiff, scaleless black lobe. 



The origin of the dorsal falls vertically before the root of the pec- 

 torals, and its distance from the caudal is less than the depth of the 

 free portion of the tail. The spines are of moderate length and 

 strength, the length of the twelfth being one-half of that of the head. 

 Some of the midrlle dorsal and anal rays are slightly produced, so as 

 to extend beyond the base of the caiidal. Caudal rounded, shorter than 

 the head. Pectoral rovmded, its length being only two-thirds of that 

 of the head. The two outer ventral rays are produced into iilaments. 



The teeth in both jaws are small, conical, in a single series ; there 

 is an incomplete second and posterior series behind the front teeth of 

 the upper jaw. The two middle teeth in the upper jaw are scarcely 

 larger than the others, whilst there is a pair of small but distinct 

 canines in the lower ; they are wide apart from each other. The 

 lower pharjTigeal plate is longer than broad, and armed with very 

 small conical teeth, those in the middle being rather coarser. 



Greenish-olive, with a large black spot immediately below the 

 fourteenth and fifteenth scales of the lateral line. Opercular lobe 

 black ; the lower lateral half of the head with rounded black spots ; 

 vertical fins with numerous oceUiform light spots, sometimes con- 

 fluent into oblique streaks. Pectoral and ventral blackish. 



Length of the specimens 4^-5 inches. 



5. ACARA*. 



Acara, pt., Keck. Brasil.Fluss-Fische inAtin. Wien. Mus. ii. 1840, p. 338. 



Body compressed, oblong, covered with ctenoid scales of rather 

 large size. Dorsal spines numerous, anal spines three or foui' ; base 

 of the soft dorsal naked or slightly scaly. Teeth in a band, small, 

 conical. Anterior prominences of the first branchial arch verj- short, 

 tubercle-like. The jaws are equal anteriorly, or the lower projects 

 beyond the upper. 



Tropical America. 



We divide the species of this genus into two groups : — 



A. Scales on the cheek in five or less series, p. 276. 



B. Scales on the cheek in more than five series, p. 282. 



A. Scales on the cheek in five or less series. 



1. Acara bimaculata. 



Acara, Marcgr. p. 168. 



Scifena bimaculata, L. Mus. Ad. Fried, i. p. 66. 



* 1. Chromis punctata, Castcln. {not Bl.) Anim.vouv. otirares del' Amir. Swd, 

 Poiss. p. 13. — Tocantins. 



2. lapidifera. Casfeln. I. c. p. 16. pi. 8. fig. 1.— Araguay. 



3. Labrus filamentosus, LacSp. iii. p. 477. pi. 18. fig. 2. — Haf). ? 



4. Hoplarchus planifrons, Kaup, Wiegm. Arch. 1860, p. 131. 



