78 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
the succeeding turn and causes it at this point to appear as the suture. 
Periphery of the last whorl well-rounded. Base moderately long, well- 
rounded. Aperture quite long, oval, posterior angle acute; outer lip thin, 
protracted a little anterior to the middle between the posterior angle and 
the base; inner lip slightly curved, rather thick, reflected over and ap- 
pressed to the base; parietal wall covered by a moderately strong callus. 
(Bartsch.) 
Type in United States National Museum, No. 13517b. Type locality, 
San Pedro, California. 
Range. San Pedro, California, to Point Abreojos, Lower California. 
Melanella tacomaensis Bartsch, 1917 
Proceedings of the United States National Museum, 53 :316; PI. 38, fig. 5. 
Shell small, straight, broadly elongate-conic, bluish-white, except where 
the animal shines through, there it appears golden brown; surface marked 
by exceedingly fine lines of growth and almost invisible microscopic spiral 
striations. Whorls flattened, separated by a scarcely defined suture; the 
basal portion of the preceding whorl shining through the substance of the 
succeeding turn appears as a conspicuous false suture. Periphery obscurely 
angulated; base short, flattened, the left margin very obliquely sloping. 
Aperture moderately large; posterior angle acute; outer lip very thick 
within, thin at the edge, decidedly protracted a little anterior to the middle 
between the posterior angle and the base; inner lip very stout, somewhat 
flexuose, reflected over and appressed to the base; parietal wall covered 
with a thick callus. Length, 5; diameter, 2.1 mm. (Bartsch.) 
Type in United States National Museum, No. 159268. Type locality, 
Tacoma, Washington. 
Range. Known only from type locality. 
Subgenus Sabinella Monterosato, 1890 
Melanella bakeri Bartsch, 1917 
Proceedings of the United States National Museum, 53:334; PI. 43, fig. 5. 
Shell small, very broadly conic, creamy-white. All of the whorls 
moderately rounded, excepting the last which is very strongly rounded. 
All marked by rather prominent lines of growth, and rather numerous 
irregularly disposed varices, of which there are sometimes several to a 
single whorl. Suture moderately constricted. Periphery of the last whorl 
inflated, strongly rounded. Base short, strongly rounded, marked like the 
spire. Aperture very large; posterior angle acute; outer lip thin at the 
edge, decidedly produced, and protracted in the middle to form a strong 
[ 376 ] 
