11H4.] NATURAL SCIENCES OF PHILADELPHIA. 265 



pair sUglitly closer to one another and about midway in snout length, 

 posterior pair close in front of eye above. Interorbital nearly level. 

 OiKTcle with a few radiating strige covered with thin skin. Upper 

 surface of head and predorsal buckler finely rugose-striate. Oc- 

 cipital fontanel begins on upper surface of interorbital opposite front 

 eye edges and extends back half way to dorsal origin. 



Gill-ojienings lateral, inferior, extend forward about opposite hind 

 pupil edge. Gill-rakers 1 + 9, short, conic, blunt at tips, -longest 

 4 in filaments and latter 2 in eye. Isthmus broad and flattened. 



Body mthout scales and exposed skin smooth. L. 1. with an 

 armature of 30 large scutes, of equal width over most of extent, 

 only becoming smaller on side of caudal peduncle, and hind edge 

 of each strongly denticulated. Exposed bony shoulder-girdle, 

 slightly swollen above pectoral base, with lengthwise striae or grooves. 



Dorsal origin a little nearer snout tip than origin of adipose fin, 

 with long strong compressed spine, its front edge antrorsely serrate 

 and hind edge also serrate, though there serrse turned forwards. 

 Adipose fin inserted a little nearer caudal base than origin of ventral, 

 fin small or about equals eye. Anal inserted before adipose fin, or 

 slightly nearer ventral origin than caudal base, first branched ray 

 longest and lower edge slightly emarginate. Caudal well forked, 

 pointed lobes equal, and rudimentary rays well developed. Pectoral 

 low, wdth large well-compressed spine, both edges strongly serrate, 

 and when distended extends back nearly to first third in depressed 

 ventral length. Ventral origin just behind dorsal base, and fin 

 reaches f to anal origin. Vent at first third in space between ventral 

 and anal origins. 



Color in alcohol largely slaty-gray above, becoming silvery or 

 whitish below. Down middle of back from dorsal base, and just 

 above each lateral series of scutes, a deep gray or nearly slaty length- 

 wise streak. Lateral scutes pale or whitish. Iris slaty. Sides of 

 head silvery-white. Fins all with general tint pale grayish to whitish.^ 

 Dorsal with subbasal blackish blotch anteriorly and extending down 

 to bases of rays. Each caudal lobe with inner basal blotch of blackish. 



Length 77 mm. 



Type, No. 39,342. A. N. S. P. Rupununi River, British Guiana. 

 J. Ogilvie. 



Related to Leptodoras Unnelli Eigenmann, but differs in the larger 

 eye and coloration. 



{Tri, three; macula, spot; with reference to the dorsal blotch and 

 the two caudal blotches.) 



