262 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ue 



non-yellow-spotted adults. It is significant that recently trans- 

 formed Zuni specimens, like certain larvae, are olive brown above 

 with small scattered dark spots and some lemon-yellow mottling on 

 the tail, thus approximating A. t. nehulosum figured by Bishop (1943, 

 fig. 45: 1,2). Only later do they develop the yellow spotting charac- 

 teristic of subadults. 



Two individuals from Molas Lake, San Juan County, Colorado, 

 kept alive for over two years, have undergone continuous color- 

 pattern change. At metamorphosis (ca. 65 mm. snout-vent) they 

 resembled A. t. utahense in the same manner as the Zuni specimens. 

 Within a week the ground color darkened and yellow spots appeared. 

 Other specimens (UMMZ 121925) preserved at this time were also 

 like A. t. nehulosum. The yellow spots then enlarged and became dull, 

 changing to olive; the original ground color was reduced to small, 

 irregular black marks. One (UMMZ 122526) died in May 1961; it 

 measures 101 mm. snout-vent. The other presently resembles UMMZ 

 120301 (see pi. 2A) from the Zunis and is 96 mm. snout-vent. A 

 single live individual from Telluride, San Miguel County, Colorado, 

 resembled A. t. nehulosum at 70 mm. but currently is closest to A. t. 

 utahense at 105 mm. 



Dark-brown, black-spotted adults taken in ponds near Telluride 

 (UMMZ 120304) and at Molas Lake (UMMZ 121926-29) are 81- 

 98 mm. snout-vent, in contrast to smaller, 63-69 mm., yellow-spotted 

 individuals taken with them. A similar size difference occurs in 

 "utahens e-\ike" adults, 92-107 mm., and "nehulosum-like" subadults, 

 68-73 mm., from the Chuska Mountains, San Juan County, New 

 Mexico (UNMCV 1111-21). I have also examined small yellow- 

 spotted and reticulated specimens from Coconino County, Ai'izona 

 (UMMZ 120302), and San Juan County, Utah (UMMZ 121931). 

 This rough correlation of size and coloration favors the hypothesis 

 of ontogenetic change. Sexual pattern dimorphism is absent; how- 

 ever, relative size at metamorphosis may influence color pattern 

 (see below). Since A. t. utahense as defined by Lowe (1955d, pp. 

 246-247) is based apparently on ontogenetic variation in A. t. nehu- 

 losum, it is suggested that this name also be placed in the synon- 

 ymy of ^. t. nehulosum. 



Color-pattern comparisons of larvae, 35-65 mm. snout-vent, from 

 the Colorado Plateau and adjacent areas reveal no basic geographic 

 differences. The coloration described by Stebbins (1951, p. 46), 

 however, may vary locally as regards density of spotting and shade of 

 ground color; for example, the specimens from Catron County, New 

 Mexico (UNMCV 1 163-68), are heavUy spotted or mottled with brown 

 and black. The tail fin has black edges, and the lateral light line or 

 row of light spots is nearly indistinct. In contrast, specimens from 



