OLDHERS BIVALEVE MOLLUSKS 93 
‘* At the mouth of Cook’s River are many species 
of shell-fish, most of them, I presume, nondescript. 
For a repast our men preferred a large species of 
the Solen genus, which they got in quantity, and 
were easily discovered by their spouting up the 
water as the men walked over the sands where 
they inhabited: as I suppose it to be a new kind 
I have given a figure of it in the annexed plate. 
"Ts a thin brittle shell, smooth within and with- 
out: one valve is furnished with two front, and 
two lateral teeth; the other has one front and one 
side tooth, which slip in between the others in 
the opposite valve: from the teeth, in each valve, 
proceeds a strong rib, which extends to above 
half-way across the shell and gradually loses 
itself towards the edge, which is smooth and sharp. 
The color of the outside is white, circularly, but 
faintly zoned with violet, and is covered with a 
smooth yellowish-brown epidermis, which appears 
darkest where the zones are: the inside is white, 
slightly zoned, and tinted with violet and pink. 
The animal, as in all species of this genus, pro- 
trudes beyond the ends of the shell very much, and 
is exceeding good food.’’ 
There are several varieties of this species, in- 
eluding var. alta, B. & S., which lives in the far 
north; it is short and broad, with a straight rib. 
Var. nuttalla, Conr., is found in Alaska and also 
in California as far south as Monterey; the shell 
is very straight, brilliantly polished, and has a 
very oblique rib. 
