66 BULLETIN 160, UNITED STATES NATIONAL MUSEUM 



The type of Bufo monksiae (U.S.N.M. No. 9896) is a young toad 

 that measures 23.5 mm. from the tip of the snout to the vent. It was 

 collected at Guanajuato by Alfred Duges in 1877. The upperparts 

 are brownish, with a few small ashen spots and a vertebral stripe of 

 the same color. A transverse light-colored band extends across the 

 eyelids and the interorbital region. It is clearly a young individual 

 of Bufo simus. It is possible that the coloration of this individual 

 may have been changed somewhat by the preservative or by the con- 

 tainer. 



The general coloration of the upperparts of Bufo simus is light gray 

 or olive, marbled with a darker shade of brown. A light-colored 

 interorbital band is generally present. The spotted pattern is espe- 

 cially noticeable on a specimen (A. M. N. H. No. 13896) from Santa 

 Catalina in Puebla. Some of the specimens collected in Jalisco have 

 nearly white underparts. A specimen (A. M. N. H. No. 13905) taken 

 at Cafetal CapaUta in Oaxaca has an unusually warty skin. Young 

 individuals of this species have a distinct light-colored vertebral 

 stripe, and many have the belly and chin spotted with white. Twenty 

 immature individuals, ranging from 32 mm. to 61 mm. in length, and 

 collected in Vera Cruz, Jalisco, and Oaxaca, have the tympanum 

 practically hidden by closely approximated conical warts. On all 

 these the tympanum is covered with a tubercular skin, and on a num- 

 ber of them the sole discernible vestige of the tympanum is located 

 in a dermal fold bordered by numerous conical tubercles. The paro- 

 toid glands are generally elongated, somewhat bean-shaped, and in 

 contact with the upper eyelid. These glands are generally studded 

 with minute pores and in rare instances are somewhat pustulose. 

 The tarsal fold is more or less distinct and generally is furnished with 

 a linear series of small closely spaced tubercles. Posteriorly diverging 

 supraciliary crests, short oblique parietal crests, and vestigial postor- 

 bital crests are generally present, except on young or immature individ- 

 uals. In a series of 50 individuals, all but two have double subartic- 

 ular tubercles on the distal phalanges of the fourth toe. 



Considerable variation in the color markings on the upperparts 

 was observed in the series studied. The skin of the upperparts is 

 generally covered with small warts, which are either conical or blunt. 

 One individual (U.S.N.M. No. 47171), taken at Dolores in Nayarit 

 on August 6, 1897, by Nelson and Goldman, differs in a number of 

 respects from the average toad of this species. The skin of the 

 upperparts, top of the head, and surfaces of the fore and hind limbs is 

 exceptionally tubercular and is covered with closely set small conical 

 warts. The elongated parotoid glands are likewise covered with 

 spinose warts. The posteriorly diverging supraciliary crests are dis- 

 tinct, but there are no vestiges of the parietals and the postorbitals. 

 The tympanum is indistinct and is covered with tubercular skin and 



