THE SMALLER SEA-SHELLS 207 
as Gyrinium californicum, is 
represented in Figure 220. 
This fine shell is more com- 
mon in the south, though 
some excellent specimens 
have been collected in Mon- 
terey Bay. The shell is very 
strong and solid, and on its 
surface are many knobs and 
ridges. It appears to grow 
forward about half a whorl 
Fig. 220, x $ and then pause and build up 
a thick lip. Leaving this ridge it goes on and com- 
pletes the whorl, and then forms another varix. 
The result of this singular method of shell-build- 
ing is that the shell has two ridges extend- 
ing from the apex to the canal, on opposite sides of 
the whorl, giving the front of the shell a some- 
what flattened appearance. The external color is 
yellowish brown, but within it is white. The com- 
mon length of one of these shells is three inches, 
though some of them grow to twice that length, 
and thus rank among our largest shells. 
On Feb. 1, 1864, Dr. Neweomb de- 
scribed a little shell, which up to that 
time had been found in but very small 
numbers. The name which he then ap- 
pled was Pedicularia californica,  Yis-221,x7 
Newe., the California Pedicularia. An enlarged 
representation is shown in Figure 221, from which 
you will see that the aperture and the outer lip are 
greatly extended and that the spire is completely 
hidden. The inside of the shell is smooth and 
