116 University of California Publications in Zoology [Vou. 17 
figs. 4-9), Boulenger (1882, pp. 284-285, 295-296), Cope (1889, pp. 
267-271), Stejneger (1893, pp. 220-221), and Dickerson (1906, pp. 
44, 113-116), to separate the so-called species boreas and halophilus 
(ineluding columbiensis) cannot, in this variable group, be considered 
diagnostic. It would appear that some of the characters originally 
used to distinguish boreas from columbiensis are of sexual rather than 
specific difference. The male of boreas has smoother skin, longer fore- 
arm and hind limb, and perhaps longer first finger than the female. 
Roundness of snout as contrasted with the truneated condition con- 
sidered as distinguishing halophilus is probably an age character, as 
also is the degree of adherence of the skin on top of the head to the 
skull. Other criteria, such as width of head, distance between eyes, 
and size of parotoid, seem to be individual differences. The “‘types”’ 
of columbiensis in the United States National Museum are all young 
specimens which I am unable to separate from boreas. Therefore, 
unless a hitherto unnoted difference exists between the toads of Puget 
Sound and those of the Columbia River, the name coluwmbiensis must 
be dropped. 
The only constant characters distinguishing borcas from halophilus 
in the specimens at hand are those of increase of pigmentation of the 
more northern form and decrease of webbing (best indicated by spread 
of hind foot) in the southern. On the basis of these two characters 
one, Bufo boreas boreas, 
inhabiting Washington, Oregon, northern Nevada, and northern Cali- 
two subspecies of boreas may be separated 
fornia as far south as Eureka, Humboldt County, Sisson, Siskiyou 
County, and Mono County; the other, a southern subspecies, Bufo 
boreas halophilus, oceurring from southernmost San Diego County 
north to the Gualala River, Sonoma County, to Oroville, Butte County, 
and to the vicinity of Independence, Inyo County. Specimens from 
localities in the intervening area show that intergradation between 
boreas and halophilus takes place. 
The above two subspecies are not easily confused if both the type 
of coloration and the ratio of spread of hind foot to total length are 
taken into account, and the followimg key may be used to separate 
them. 
1. Back either dark and unspotted or blotched and speckled between the blotches 
with small, dark dots on the light background; spread of hind foot from 
end of first to tip of fifth toe usually more than 36 per cent of the total 
body-length; maximum body-length 120 millimeters —_.. Bufo boreas boreas. 
1’. Back usually spotted or blotched (rarely with dark speckles between the 
blotches on the light background) and seldom wholly dark; spread of hind 
foot usually less than 36 per cent of total body-length; maximum body- 
Ten othe) Ol ernie 61: eerste eee tee nena aera Bufo boreas halophilus. 
