THE SMALLER SEA-SHELLS 187 



to be properly classified. Descriptions of a very few 

 of the larger forms will now be given, and the names 

 of some others which occur in our territory will be 

 given in the alphabetical list of shells, near the end 

 of the book. For a careful study of this family we 

 are most haf)py to refer the student to Bulletin 68, 

 of the United States National Museum, entitled, 

 "A Monograph of West American Pyramidellid 

 Mollusks by William Healey Dall and Paul 

 Bartsch." It was published at Washington late in 

 1909, after years of careful research. To learn more 

 about it write to the Secretary of the Smithsonian 

 Institution. 



Fyramidella adamsi^ Cpr., (P. conic a^ var. 

 variegata), the Obelisk-shell. This little 

 shell is shown in Figure 177. The surface 

 is marked with fine lines of growth. There 

 is an external fold on the columella which is ^'^- ^''^ 

 not well shown in the little cut. The shell is brown- 

 ish in color, somewhat clouded. It is found in south- 

 ern waters, but it is quite rare even there. 



l^urhonilla castanea^ Keep, the Chestnut 



Turbonilla, is shown in Figure 178, the little 



/ M cross denoting the true size of the shell. Its 



"T ^ eight or ten whorls are marked with numer- 



Fig. 178 ous fine axial ribs, and though it is so small 



it is a beautiful shell. Its color is chestnut 

 brown, as might be expected from its name. It is 

 found at San Pedro and San Diego. The general 

 shape of all the Turbonillas is shown in this figure, 

 but they differ much in sculpturing, number of 

 whorls, and other particulars. 



