Shell Selection of Hermit Crabs-— -Orians and King 
303 
shells of Thais emarginata , leaving shells of 
Tegnla and Callio stoma for Thais even when 
the latter were so small as to preclude the with- 
drawing of the carapace into the shell Never 
did a crab leave a Thais for shells of the other 
two species, and in every case in which crabs 
were forced to use Tegula and Callio stoma they 
left them as soon as a Thais was again made 
available. P. samuelis and P. granosimanus , on 
the other hand, showed no preference between 
shells of Tegula funebralis, T. brunnea , and Cal- 
liostoma costatum as long as the shell was of 
proper size. A marked preference for shells of 
Tegula was noted for P. samuelis in southern 
California by Coffin (1954). However, adult 
P. granosimanus were so large that only Tegula 
H|| 
S&fe&i# - >60% 
i 30 - 60% 
- <30% 
I 
Fig. 3. Trellis diagram showing overlap in shell utilization in four samples of Eniwetok pagurids. 
