14 WEST AMERICAN SHELLS 
farther to the north, and was once called the Van- 
ecouver variety of the last species. They exist 
side by side, however, off the coast of California. 
Hemithrys psittacea, Linn., the Parrot Lamp- 
shell, is a northern species found in both oceans. 
Figure 6 represents a young specimen, showing 
Fig. 6, x 3 (*) 
The last member of the brachiopods 
the complete shell and the in- 
teriors of the two valves. The 
shell is thin, translucent, and of 
a yellowish gray color. This 
species has been dredged from 
the far north to San Diego, 
out of water sometimes nearly 
a mile in depth, where the tem- 
perature was well down 
towardsethe\ Gecormetartam 
The form here shown was once 
believed to be distinct, and was 
described under the name of 
Frieleia hall, Dall. That is 
now regarded as a young stage 
of the older species. 
to be described is closely related to some 
of the shells that are found in the oldest 
of the fossiliferous rocks. Perhaps, 
therefore, it has a direct pedigree reach- 
ing back farther than that of any other 
shell in the world. Its name is Glot- 
tidea albida, Hinds, the White Tongue- 
shell, (Lingula albida). It extends from 
Monterey to Lower California. I once gathered a 
few specimens from the mud flats of San Pedro,- 
