198 MOLLUSCA. 
Inhabits the rocks at the mouth of the harbour of San Francisco, 
California. Dr. Pickering. 
Remarkable for the amplitude of the aperture, the broad excavated 
columella, and the apparent grinding away of a portion of the adjacent 
whorl by the operculum, and perhaps really so, as it is the part where 
the opercle would lie when the animal was protruded. It may be 
L. planazis, Nuttall, no description of which has been published. 
Figures 237, 237 a, two views of the shell. 
Lirrorina CALIctInosa (Gould). 
Testa parva, ovata, tenuis, levis vel lineis incrementalibus striata, 
epidermide fusco-virente luteo-maculato induta: spira apice erosa, 
anfractibus quatuor ad quinque, ventricosis ; sutura profunda: aper- 
tura viz dimidiam longitudinis teste adequans, rotundato-ovata ; 
labro continuo, acuto, pallido, vix everso ; fauce hvida. 
_ Littorina caliginosa, Gouin; Proceed. Boston Soc. Nat. Hist., ii. 
83. March 1849. Expedition Shells, 53. 
SHELL small, thin, smooth, or with faint lines of growth, ovate, 
covered with a deep grass-green epidermis, variegated with minute, 
scale-like, irregular spots of ochreous yellow: spire eroded at tip, of 
about four or five very ventricose whorls; suture deeply impressed : 
aperture less than half the length of the shell, rounded ovate; lip 
continuous, sharp, a little everted, pale; base with a slight tendency 
to an umbilicus; throat dark livid. 
Length one-fifth of an inch; breadth one-eighth of an inch. 
Inhabits Tierra del Fuego. Couthouy. 
This small shell has the general form and characters of L. tenebrosa, 
and its structure and colour give it somewhat the appearance of a 
fresh-water shell. I believe it was found adhering to floating kelp. 
A box of smaller specimens, marked ‘ N. Holland,’ seem to be so near 
