18 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 
Some West American Shells—Including a New 
Variety of Corbula Luteola Cpr. and Two 
New Varieties of Gastropods. 
By Mrs. M. Burton Williamson. 
In his recent volume on West American Shells, Prof Josiah 
Keep lists 1,871 land, fresh water and marine mollusks. Allow- 
ing for a few dupheates that have inadvertently been listed, 
this list, if correctly numbered, with nine Mangilias and one 
Cancellaria that should be added, would make it reach 1,377 
species. This is, by far, the longest list of West Coast shells 
that has been published. 
But even this fine showing leaves several names that should 
be added. In my own collection there are a number that are 
not found in the list. Some of these may possibly be among 
the synonyms, but, for the most part they will be found new 
LOmate 
There is always a difference of opinion as to the value of a 
‘‘variety’’ or varietal names, but, if they are listed for one 
species there can be no valid reason for omitting them from 
another—seeing that all classification is somewhat arbitrary. 
But with the elimination of such names from the following the 
list might still be found worthy of mention. As this list, with 
the exception of Uvanilla from San Clemente Island and one 
other shell, represents shells in my collection the limit of the 
article is necessarily restricted. Only marine forms are noted. 
No attempt has been made, in this list, either at synonomy 
or bibliography; an occasional reference is given to recent 
works, (excepting Carpenter’s and Cooper’s), that would fur- 
nish a clew for further information. 
AVICULIDA 
Genus Avicula Lamark 
Avicula sterna Gould. 
Young specimen, Marine Ways, San Diego, Cal. Collected by 
Miss Polhamus and received from Dr. James Perrin Smith, 
Prof. Paleontology Leland Stanford Jr. University. 
While found upon our California Coast this species may have 
to be classed among the adventitious ones. Dr. Wm. H. Dall, 
to whom the shell was referred, says of it that it ‘“Was doubt- 
less scraped off some vessel from the Gulf, as it has not been 
reported from North of the Gulf hitherto. A number of species 
have been obtained from the Ways where they haul small 
vessels up at San Diego, including a Discinisca and an Acmea, 
