LAMP-SHELLS AND THEIR ALLIES 19 
which is a kind of horny covering on the outside of 
the shell that is found in some species. With these 
simple explanations we will pass on to a deserip- 
tion of the species, leaving a fuller account of the 
animal to the books on zodlogy, merely remarking 
that the shell is secreted by the mantle. 
The first shell of this great class that we are 
to consider is one that 
very few will ever col- 
lect, for it lives in the 
ocean where the water 
is very deep, from one 
to two miles being re- 
eorded by the ‘‘Alba- 
tross’’? at some of the 
stations where it was 
dredged. Its name is 
Solemya johnsoni, Dall, 
which may be rendered 
into English as John- 
son’s Solemya. It is a 
singular shell, with fin- 
gers of epidermis reach- 
ing out nearly an ineh 
beyond the edge of the 
firm portion. The whole 
shell is about four and 
a half inches long. It 
has been dredged from 
deep water off various parts of the coast as far 
north as Puget Sound. 
Fig. 8,x $ (*) 
