MUSEUM OF COMPARATIVE ZOOLOGY. 165 
irregular in shape. A few lines may also be dropped, perhaps some added, or the 
entire surface may be modified in obedience to the laws of the mechanical skill 
possessed by the individual, and the affinity of matter secreted by the animal, for 
the purpose of constructing the shell. An examination of a large number of 
Selenites concanus, and of our West Coast forms, convinces one that the entire group 
of American Selenites is the offspring of a single common type. 
The above is Mr. Hemphill’s description, from “ The Nautilus,” Vol. IV. 
p- 42, 1890. 
Selenites Duranti, var. Catalinensis, Hrmrmtr. 
Plate II. Fig. 3. 
I figure an authentic specimen. See Third Suppl., p. 221. 
Selenites Vancouverensis, var. transfuga, HEMPHILL. 
Shell very much depressed, planulate, broadly umbilicated, of a dirty white 
color; whorls 34 or 4, flattened above, more rounded beneath, with regular strong 
rib-like striæ; suture well impressed, becoming deeper and channel-like as it ap- 
proaches the aperture; aperture hardly oblique, slightly flattened above, with a 
tendency to a corresponding depression below ; lip simple, roundly thickened inter- 
nally, its terminations approaching, forming in some specimens a short columellar 
lip, joined by a heavy raised callus in very adult specimens. Height 7; inch, 
greatest diameter 7%, lesser 77; inch. 
San Diego, California, to Todos Santos Bay, Lower California. 
This is the small flat shell that has been distributed as a variety of sportella, and 
also as a variety of Voyanus. I find, however, on comparing it with the typical 
Voyanus collected by me last fall, that it is quite a different shell. The ribs are 
closer and finer than either sportellus or Voyanus, the umbilicus is much larger, 
and it is a very much more depressed shell. I consider it, however, a deserter from 
the Northern forms, and name it accordingly. It is a much Irrger and a more 
globose form than simplilabris of Ansey. 
The above is Mr. Hemphill’s description. 
Selenites Vancouverensis, Lea. 
The only differences that I can detect between this shell and Selenites concava, 
Say, are these. The umbilicus in the California shells is a little more contracted, the 
color is a shade darker, the striw are a little closer, stronger, and more regular, and 
the body whorl is a little more flattened at the aperture. Height § inch, breadth 
4 inch. 
Sonoma Co. to Santa Cruz Co., California. 
The above is Mr. Hemphill’s description of what he calls S. concavus, var. 
occidentalis. 
