40 
University of California Publications in Zoology [Vol. 27 
KEY TO KNOWN LARVAE OF CALIFORNIA AMPHIBIA 2 
• PAGE 
1. Head broader than and distinct from body; both fore and hind limbs 
developed at an early stage; external gills present on neck region, not 
covered (pi. 6, fig. 12) ; mouth parts adapted for swallowing animal (insect) 
food Order Cauda ta 
2. General body coloration chiefly plain yellow with two conspicuous longi- 
tudinal stripes of black, one along either side of dorsal fin; size at 
metamorphosis usually under 60 mm .Triturus torosus 46 
2'. Body coloration usually mixed black and yellow, or brown and yellow, 
but never with lengthwise stripes; vomerine teeth well developed on 
roof of mouth in U-shaped pattern; size at metamorphosis often more 
than 60 mm. 
3. Dorsal tail fin extending forward only to above base of tail 
Dicamptodon ensatus 78 
3'. Dorsal tail fin extending along full length of body to above axillae. 
4. Body coloration mixed light and dark brown with numerous 
round dots (0.5 mm.) of yellow on lateral and ventral surfaces. 
Amby stoma paroticum 7 5 
4'. Body coloration yellow and black, without small light dots 
Ambystoma califomiense 6 1 
1'. Head not distinguishable from body, the two fused into a common ovoid 
mass; gills covered soon after hatching by a thin opercular membrane; 
limbs not in evidence until late in development (pi. 6, fig. 12; pi. 16, fig. 49); 
mouth parts adapted for rasping, but not for swallowing large particles .... 
Order Salientia 
5. Spiraculum median, a transverse slit on ventral surface, posterior to 
‘chin’; upper jaw in form of transverse band of black horny material; 
lower jaw reduced to a black dot hidden beneath upper; labial teeth 
in 6/7 (3/l0) rows (text fig. KK) Ascaphus truei 144 
5'. Spiraculum on left side of body near middle; upper jaw slightly bowed in 
outline, lower jaw well developed; labial teeth in 7/5 or fewer rows. 
6. Anus median, emerging in ventral fin. 
7. Body wider posteriorly than anteriorly; eyes well up on top of 
body (pi. 10, fig. 30); tail fins very broad; ventral surface with 
bluish or reddish iridescence; total length up to 72 mm.; labial 
teeth in 2/4 rows, only the first and fifth rows extending across 
mouth region; mouth region entirely circled with papillae 
(text fig. EE) Scaphiopus hammondii 149 
7'. Body tapered behind, broadest anteriorly; eyes near sides of body; 
tail fins narrow (pi. 16, fig. 49, lower two larvae); body solidly 
blackish; labial teeth in 2/3 rows; papillae only at sides of 
mouth region Genus Bufo 
8. Size larger, up to 55 mm. total length; lateral margin of mouth 
region with papillae on both upper and lower halves; lower 
labial teeth in three graduated rows, lowest row shortest 
(text fig. FF); not found on deserts of California 
Bufo boreas halophilus 171 
2 The method of describing the larvae follows that of Boulenger (1891) and Wright (1914). 
