270 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ue 



juniper grassland and Plains-Roughlands continuum around Grants. 

 A single chorus observed at 6400 feet, July 4, 1954, after a heavy rain, 

 consisted of more than 100 calling males in a small cattle tank on 

 soil-covered lava adjacent to the rough Grants malpais (Gehlbach, 

 1956, p. 365). Scaphiopus hammondi was present in about equal 

 numbers in the breeding aggregation. 



Locality records: 



VALENCIA CO.: 11.5 mi. SSE. Grants (CU 5766); Grants (Smith, 1950, fig. 45). 



Bufo woodhousei woodhousei Girard x H. w. australis Shannon 



and Lowe 



Rocky Mountains toads in Arizona recently have been split into 

 two races (Shannon and Lowe, 1955). The nominate, northern 

 subspecies is now considered to occupy the Colorado Plateau in that 

 state; it is separated presumably from a new southern, lowland form, 

 B. w. australis, by the MogoUon Plateau. Shannon and Lowe (1955, 

 pp. 188, 190) included New Mexico within the range of B. w. australis 

 but did not state specific localities. B. woodhousei from the Zuni 

 region does not conform readily to either subspecies. Geographically 

 these toads might be expected to resemble typical B. woodhousei, 

 but structurally they combine some characters of B. w. australis with 

 B. w. woodhousei and are considered intergrades. 



With regard to diagnostic features, 22 adult specimens have: 

 (1) frontal area of craDium elevated m 91 percent; (2) snout-vent 

 length/parotoid gland width 10.6-13.9 (x 11.9±0.19); (3) snout-vent 

 length/parotoid gland length 4.4-5.6 (5.1 ±0.74); (4) skin of upper 

 surfaces smooth; (5) median white line on snout present in 82 percent; 

 (6) black pectoral semicircles not strongly developed; (7) dorsal color 

 brown with 68 percent having large warts set in black. Characters 

 1, 2, 4, 5, and 6 favor allocation with B. w. woodhousei, while 3 and 7 

 are closer to B. w. australis. 



Colorado Plateau populations of B. woodhousei should be more 

 or less uniform in the Zunis and adjacent Arizona since no important 

 barriers to east-west dispersal exist. Such continuity is shown, for 

 the characters of B. w. woodhousei predominate in the specunens at 

 hand. The features of B. id. australis, however, indicate that gene 

 flow from the south occurs if, in fact, these features are sufficient to 

 distinguish B. w. australis from the nominate form in New Mexico. 

 Irrespective of the validity of the taxonomic characters involved, the 

 Rio Grande valley and associated lowlands provide a suitable path- 

 way for north-south gene flow in central New Mexico (see discussion 

 under "Zoogeography," p. 315). 



Although Shannon and Lowe (1955) furnish ratios of parotoid gland 

 size to body length, they do not limit these criteria to any certain age 



