42 U. S. NATIONAL MUSEUM BULLETIN 2 06 



two large white triangles extending inwards from the parotoids, their 

 apices nearly meeting on the occiput and their bases continued onto 

 the upper eyelid and along the dorsolateral line to the groin; the 

 remainder of the dorsal surface is rich burnt umber, with a pair of 

 irregular white concentric markings just anterior to the sacral hump. 

 A less accentuated but similar style of coloration is seen in one or two 

 of the Teresopolis frogs, as well as in a young one from R.io Canaburi 

 in Amazonas, UvSNM 83548, and in several from Panam^, The 

 ventral region may be pale, or spotted with brown or almost entirely 



Figure 4. — Bufo typhonius, USNM 108987, from Maroni River, British Guiana, showing 

 extreme development of head crests; X 1. 



brown with minute brilliant yellow dots on the throat. The largest 

 Teres6polis specimen, USNM 97711, is 49 mm. long; one from Sal to 

 da Hud, USNM 83571, exceeds it by 4 mm., but an example from 

 Ecuador measures 78 mm. 



The usual well-marked black thumb of the male, a valid secondary 

 sexual character in most species of Bufo, is of no value in determining 

 sex in this species, since black spots on the joints of the thumb occur 

 as part of the color pattern of nearly all specimens. The thumb 

 joint does not seem to become swollen at breeding season in males on 

 typhonius, hence internal dissection must be resorted to, except of 

 egg-bearing females, in order to ascertain the sex. 



An enormous development of the supratympanic crests occurs in 

 USNM 108987 from British Guiana. The parotoids are completely 

 overgrown b}^ the crests, which double the normal height of the head. 



Specimens examined 

 BRAZIL: 



Amazonas: Cachoeira Panela de Onga, USNM 83548, Holt, Nov. 1, 1930. 

 Hyutanaha, USNM 28938-9, Steere. Manslos, NMS, — , Triebel. Rio Cana- 

 buri below mouth of Rio Maturaca, USNM 83549, Holt, Nov. 6, 1930. 

 Salto da Hud, USNM 83552-3, 83555, 83559-60, 83571, and 83577, Holt, 

 November-December, 1930. Sao Antonio de Rio Madeira, CM 2611, 

 Haseman, Nov. 2, 1908. 



Bahia: Bahia (?), AMNH 38556, Beck, 1914; 



Itaet6, MRHN IG 9308, Reg. 37b, Massart, December 1922 

 Serra do Palhao, USNM 102313 and MP 2041. 



