24 WEST AMERICAN SHELLS 
Glycymeris intermédia, Brod., the Medium Ark- 
shell, is round lke a button, and is about half an 
inch across. The shell is solid, white, though 
tinged with brown, and its inner edge is finely 
erenulated. The hinge area is crescent-shaped, 
and is marked with many small, transverse hinge- 
teeth. It was formerly called Aaxinea intermedia. 
Figure 11 repre- 
sents both the in- 
side and outside of 
a remarkable shell 
from northern 
Alaska. As it was 
dredged from pret- 
Wi 
4 is st ae RN <e 
GY pS . xX “: 
Gi). OS 
Hsp oh WAGON ty deep water, it is 
ww AN i KAS probable that very 
NHN few of my readers 
(SE™ Fig. 11, x 4 (*) will ever see a 
specimen; but it is 
well to know about 
some of the rare 
forms that live in 
the sea, even if we 
never have _ the = 
privilege of seeing %-. iy 
them. The epider- Ge aes i ‘ 
mis is densely Deere 
haimy amd on a Fig. 11, x 5 (*) 
brown color. The margin of the shell is curiously 
bent, making a deep pit behind the hinge. The 
name is Limopsis vaginata, Dall, and we will call 
it the Bearded Ark-shell. 
