188 JOURNAL OF ENTOMOLOGY AND ZOOLOGY 
parallel, more arched. They were lighter in color and more 
distinctly marked than the males. These differences are prob- 
ably only sexual. 
These specimens appear to lie close to Pentidotea whiter in 
many details, but in others are quite different. The male of P. 
whitei is described as being much larger—17 mm. by 34 mm.— 
and about three times as long as wide, whereas the male of these 
Laguna specimens is almost four times as long as wide. In 
P. whitei the epimeron of the second segment becomes narrower 
from the anterior to the posterior margin. Here the epimeral 
suture is practically vertical and the epimeron is about as wide 
anteriorly as posteriorly. The anterior margin of the head is 
more distinctly excavate and the antero-lateral angles more 
pronounced than in P. whitei. The eyes are about round, whereas 
in P. whitei they are twice as wide as long. The last abdominal 
segment is more elongate and the terminal process more pro- 
nounced than in P. whitei. It therefore seems evident that this 
isopod represents a new species. 
