198 University of California Publications in Zoology [Vol. 27 
whistling" noise of four or five seconds duration with about the same 
interval, the throat swelling considerably while doing so. Dickerson 
(1906, p. 112) says that the “ dusky throat can extend into a large 
rounded vocal pouch.” 
The breeding season seems to be rather late, considering the nature 
of the territory occupied. In Death Valley the toads were in chorus 
and spawning at the end of the first week of April in 1917 (Grinnell, 
MS). In the Turtle Mountains Camp (1916a:, p. 512) found larvae 
and some metamorphosed young toads on May 28, 1914, which he 
referred to this species. The metamorphosing young measured 9.4 to 
10.5 millimeters in head-and-body length, and in life they were dotted 
on the back with many small red tubercles surrounded with indistinct 
black circles, a color pattern distinctive of the adults of punctatus. 
The life-history in relation to the environment. — Bufo punctatus 
ranges over practically the entire desert area in the southwestern 
United States and northern Mexico. However, the proportion of the 
region actually occupied by this species is extremely small ; its range 
is decidedly ‘discontinuous.’ The scarcity of records for Bufo punc- 
tatus, as compared, for example, with those for Scaphiopus ham- 
mondii, is striking. Punctatus was seldom found by early naturalists 
and even at the present time its stations of record are few and far 
between. The northern boundary of its range is still imperfectly 
known. Only in Death Valley and the Grand Canon has this species 
been met with in any numbers. Ecologically, punctatus is restricted 
to desert canons containing seepage or springs. Its present wide 
general distribution was probably accomplished at some time in the 
past, when less arid conditions prevailed on the southwestern deserts. 
The distribution of Bufo punctatus compares closely with that of Hyla 
arenicolor and the factors controlling the ranges of the two are prob- 
ably somewhat similar. Arenicolor requires actual running water, 
whereas punctatus seems content with mere seepage, a later stage in 
the history of a regressive stream. 
If, as is contended by some writers on southwestern climate (e.g., 
Huntington, 1914), the ‘American deserts’ are experiencing a pro- 
gressive desiccation, then Bufo punctatus in particular among the 
desert amphibians is probably losing in numbers and territory as a 
species, for it apparently occupies an extreme position with regard 
to limitation in moisture requirements. If the evolution of the habitat 
precedes the evolution of the species, then removal of the habitat 
means disappearance of the species no matter how prolific or how 
