370 U. S. NATIONAL MUSEUM BULLETIN 206 



Eyelids appear dark because of their translucence which permits the 

 dark eyeball to show through them. 



Remarks.- — ^As yet, only this one species of Microhyla has been found 

 in the three states under consideration. 



Microhyla subnigra agrees with its relative M. schirchi from Rio 

 Mutum, Esplrito Santo, in having the toes not dilated; the latter, 

 however, has a rudiment of a web and the skin of the head adherent 

 to the skull, while the former has the toes free and the head skin 

 smooth and not adhering to the skull. 



M. microps from the Guianas and Brazil has the toes, except the 

 inner one, dilated into small but distinct disks, with a groove separat- 

 ing their upper and lower surfaces. 



Specimens examined 



BRAZIL: 



Rio de Janeiro: Guapi, Teres6polis, USNM 97718, Sandig, April 1935. 



Teres6polis, Lutz Coll. — (1), Venancio, April 1945. Serra de Maca6, MP 



(type of Engystoma sub-nigrum). 

 Sao Paulo: Ribeirao Pires, ZSBS 5, Bresslau, November 1913. 



Genus Stereocyclops Cope 



1870. Stereocyclops Cope, p. 165. — Carvalho, 1948, p. 4. (Genotype, Stereo- 

 cyclops incrassaius Cope.) 



Generic diagnosis. — The diagnosis of Carvalho is translated as 

 follows : 



Cranium toothless, depressed and wide, much wider than long, with a parabolic 

 outline. Ethmoid divided. Prevomer divided, median anterior portion forming 

 the median internal border of the choanae; postchoanal portion present, long and 

 narrow, within the proximity of the median anteroposterior line of the cranium, 

 in width more or less uniform, superposed on the palatine, going up to the half of 

 the latter, where it is united. Ossicles of ear developed. 



Clavicle and precoracoid present and well developed, extending from the scapula 

 to the median anteroposterior line of the sternum. 



The clavicle is much recurved, forming almost a right angle in its proximal 

 extremity with the scapula. Omosternum absent. Sternum large, cartilaginous. 

 Vertical column diplasiocoele, the transverse apophyses of the eight presacral 

 vertebrae long, so that those of the third vertebra exceed those of the sacrum. 

 Urostyle longer than the rest of the column. Sacral vertebrae with long apophyses 

 becoming flat and widening progressively, in proportion as they go away from the 

 body of the vertebra. Terminal phalanges simple. Pupil oval, horizontal, some- 

 what rounded. Tongue entire, oval, having the posterior half concave and free. 

 Two transverse folds on the roof of the mouth; the first smaller, smooth, between 

 the apertures of the Eustachian tubes and the second larger, in the beginning of 

 the aesophagus, with its posterior border free and fringed. Tympanum indistinct. 

 Fingers of the hand in the following order of increase 1-2-4-3, having nevertheless 

 1, 2, and 4 almost equal, those of the foot 1-2-5-3-4. 



