NO. 3652 ISOPODA AND TANAIDACEA—MILLER ai | 
1936; Nierstrasz and Schuurmans Stekhoven, 1941; Hatch, 1947). 
Richardson (1905b) gives its southern limit as Monterey Bay, Calif., 
but Thielemann (1910) states it occurs as far south as San Diego. 
Menzies and Barnard (1959), however, do not list it among the marine 
isopods of the southern California coastal benthos. The author has 
specimens from San Simeon, some 100 miles north of Point Concep- 
tion, which divides the warm water coastal fauna of southern California 
from the colder water fauna of central and northern California. 
Richardson (1905b) records depths from the surface to 9 fathoms 
(16.4 meters). It is found commonly on kelp exposed at low tide. 
On buoys, it was found generally at or near the waterline. 
Idotea (Pentidotea) stenops (Benedict) Menzies 
FIGuRE 3 
Locatiry.—California: San Simeon Bay (Station 73). 
Remarxs.—ZIdotea stenops has been reported from Monterey Bay, 
Calif. (Richardson, 1905b); Coos Bay, Oreg. (Hatch, 1947). The 
author has collected it among algae in the low intertidal zone at several 
localities along the central California coast from Moss Beach (San 
Mateo County) to Stockhoff Cove (Sonoma County). 
No depths are reported in the literature for this species. On the 
buoy at San Simeon, it was found at the surface with Jdotea resecata. 
Synidotea laticauda Benedict 
FiGurE 3 
Locatitres.—California: greater San Francisco Bay (Stations 76, 
79, 82, 83, 87). 
Remarxks.—The distribution of Synidotea laticauda is limited to 
greater San Francisco Bay, with localities recorded in all three di- 
visions—southern (lower), middle (central), and northern (upper) 
divisions (Richardson, 1905b; Filice, 1958; author’s collection). The 
northern division includes San Pablo Bay, Carquinez Straits, and 
Suisun Bay as far inland as Pittsburg near the mouth of the Sacra- 
mento-San Joaquin River delta. It has never been collected on the 
open coast outside the bay. 
On buoys, Synidotea laticauda was taken at various depths from 
the surface to 7.4 meters. Richardson (1905b) records it at 12.3 
meters. On several buoys, large numbers of these isopods were taken 
feeding on hydroids Bimeria franciscana Torrey. 
Many environmental factors, alone or in combination, doubtless 
limit the distribution of this species to San Francisco Bay. Prominent 
among these are salinity, temperature, turbidity, oxygen content, and 
tidal and river currents. Quite as important ecologically as average 
conditions with regard to these factors are the fluctuations and 
extremes. Special conditions are created by the geography of this bay 
