1914.] NATURAL SCIENCES OF PHILADELPHIA. 278- 



of posteriorly dirpctod spines, and short fifth series on lower side of 

 caudal peduncle and caudal base. Each of these spines in length- 

 wise series well separated, with one or more smaller or minute spines 

 scattered around basally. Thus indications of lateral plates, ill- 

 defined at first, though well-marked on caudal peduncle and caudal 

 base, corresponding to squamation, are formed. Anteriorly lower 

 series of lengthwise spines originates on bony plate over base of 

 pectoral spine. Predorsal and postdorsal regions of back with, 

 minute spines, also lower surface of caudal peduncle and lower 

 surface of trunk above anal base. All spines of fins and sides of 

 larger rays spinescent, latter condition varying from quite large 

 strong denticles on front of pectoral spine to those very minute on. 

 fin-rays. L. 1. not evidently developed, median series of lateral 

 spines in no way differing from others. ^ 



Dorsal origin about midway between that of adipose fin and 

 snout tip, spine rather slender and with somewhat flexible tapering, 

 tip, fin quite large and all rays well developed. Adipose fin mod- 

 erately large, spinescent, inserted little nearer last dorsal ray base 

 than caudal base, fin about | an eye-diameter in length. Anal 

 inserted just after dorsal base, with slender and rather flexible spine, 

 first branched ray longest and extends back about f to caudal base. 

 Caudal large, emarginate, both outer rays enlarged and spinescent.: 

 Pectoral low, with very strong spine, reaches f to ventral origin. 

 Latter inserted below first branched dorsal ray base, with strong 

 spine rather flexible at tip, fin extends beyond anal base slightly, or 

 about f to caudal base. Vent with short tube, placed at last f in 

 space between ventral and anal origins. 



Color in alcohol very dark or dusky generally, especially above. 

 Everywhere more or less with large close-set blackish blotches,. 

 spots, or short vermiculatioiLs, on upper surface more or less obscured 

 by bristles or spines, though below,,very conspicuous. General tint 

 of lower surface much paler than back, thus adding to contrast. 

 All fins with similar Ijlack blotches, the pale intervening areas often 

 forming more or less into narrow transverse pale lines. Caudal 

 with lobes distally somewhat chestnut-brown above and below, 

 median portion of fin, however, with large blackish blotches like on 

 trunk and narrow pale areas intervening. Iris slaty, also disk. 

 Teeth worn brownish at tips, whitish basally. 



Length 92 mm. 



Type, No. 39,345, A. N. S. P. Rupmiuni River, British Guiana. 

 J. Ogilvie. 



