NATURAL SCIENCES OP PHILADELPHIA. 131 



those of the sides and forearm conic : soles rough, weh short, metatarsal tu- 

 bercles small, obtusely prominent; tarsal fold scarcely visible. Heel to 

 axilla. Two obtuse metacarpal warts. 



Gray brown ; a yellow vertebral line, with numerous chestnut brown light 

 bordered spots on each side. Sides with two longitudinal brown bands, one 

 from parotoid and one from groin. Limbs irregularly light varied above. 

 Under surfaces immaculate. 



Length of head and body 2 in. 6 1. ; breadth at angle of jaws below 1 in. 

 Length of fore limb 1 in. 5 1. ; length of foot 1 in. 3 1. 



Arriba, Costa Rica, C. N. Riotte. Smithsonian, No. 6490. 



This handsome species resembles the B. ocellatus Gthr. in coloration. 



Phyllobates ridens sp. nov. 



The close areolation of the ablomen, throat, and lower face of femora, the 

 recurved angle of the mouth, the minute (one-eighth orbit) tympanum above 

 the ordinary position, and truncate tongue, are marked features in this species. 

 The tongue is broad and extensively free, and each angle behind is thickened. 

 Choans small, Eustachian ostia minute. Skin smooth, without folds or tu- 

 bercles, except a few wartlets over orbit. The eyes are large and prominent, 

 diameter of orbit nearly equal from same to end of muzzle. Latter projecting 

 beyond jaw, nares behind the tip, each on an angle of cauthus approximated. 

 Canthus strong, a little concave ; loreal region oblique. Greatest width of 

 head (behind) equal to length of same, and entering 2 in total. Heel and 

 palm to end muzzle. Fingers and toes long, free, dilatations well marked. 



Color above grayish brick red, with a gray cross bar between eves, two 

 across tibia and three across femur. Sides with some gray shades, lip with 

 five bars of the same, two from the orbit. A black spot on tympanum, and 

 gray line on canthus. Below, and inner faces of limbs pale brownish. 



Habitat. St. Juan River, Nicaragua, Robt. Kennicott ; Mus. Smithsonian. 



Engystoma variolosum sp. nov. 



Two strong compressed metatarsal tubercles, a sublongitudinal cuneiform 

 and subtransverse opposite it : toes slightly webbed. Width between tym- 

 panic regions nearly double the length from muzzle to nuchal fold. Muzzle 

 prominent, as long as orbit, nostrils nearly terminal. Mandible with two 

 symphyseal notches, and median knob. Tongue flat, elongate ; slits of vocal 

 vesicle large. Heel to front of scapula. 



Dark brown above ; under side limbs and belly darker, with numerous 

 large yellowish spots. Sides anteriorly blackish brown, which has a serrate 

 margin above. Femora, forearms and tarsi same behind, with coarse yellow 

 vermiculations : some yellow spots behind the angle of the mouth. Length 

 of head and body 1 in. 4-5 1. ; of posterior limbs 1 in. 7 1. 



This species resembles the East Indian species called Diplopelma by Giin- 

 ther, on account of the palmate feet: if this is the only ground of distinction, 

 the genus must be united with Engystoma. 



Arriba, Costa Rica ; Chas. N. Riotte. Mus. Smithsonian, No. 6486. 



Engystoma ustum. 



This animal agrees with the preceding in it s two metatarsal tubercles, but 

 they are less acute, the exterior being only an acuminate wart. Toes entirely 

 free. Muzzle more prominent than in the last or E. ca ro li n e n s e, little 

 longer than orbit ; head larger relatively than in the last mentioned species, 

 with which it agrees in size. Width of cranium at tympanic region less than 

 1J times from muzzle to nuchal fold. 



Length of head and body 11 lin. ; posterior limb 12 lines. 



Deep brown above, yellowish brown below, with numerous approximated 

 pale spots, which extend slightly on sides. Limbs unicolor. 



Habitat. Guadalaxara, West Mexico. I. I. Major. 



The E. carolinense never exhibits more than one metatarsal tubercle. 



1866.] 



