R. Zweifel April 4, 1952 77. Rana boylii boylii Arroyo Mocho, 9.5 mi. SE Livermore Alameda Co., Calif. 8 small frogs were collected and about 20 more seen in a stream which flows into Arroyo Mocho from the north. The stream is 4 feet wide at the widest and one foot dep. The gradient is sufficiently steep that rapids or small waterfalls occur every few feet for much of the course. Water temperature was 19°C. The eight frogs agree generally in dorsal pattern - many faint 2-3mm spots on greenish-brown background. The spots are slightly darker than the background. Lateral barring is indistinct. Dark throat markings are present, but not as well defined as in the north coast frogs.