56 SFL mF pemer car noe IGE ERE RRR 
cided lines of growth; dull white without, pearly and shining 
within; Indian name is goeduck. 
21:0743 Panope generosa solida Dall, 1898. 
Straits of Fuca, to San Francisco bay, Cal. 
21:0744 Genus Pleurodon Wood, 1840. 
21:0795 Pleurodon (Cyrilla) munita Carpenter, 1898. 
Santa Barbara Islands, Cal., to Gulf of Cal. 
21:0746 Genus Poromya Forbes, 1843. 
Animal with unequal siphons, clothed with numerous fla- 
ments, foot narrow and slender. Shell suborbicular, subequi- 
valve, and inequilateral, thin, transparent, slightly mnacreous 
within; valves closed, surface granulated; teeth, in right valve a 
short but strong cardinal, and in the left a minute triangular 
cardinal and a ridge-like lateral on the posterior side. About 25 
recent, Cretaceous and Eocene species. 
21:0747 Poromya (Dermatomya) tenuiconcha Dall, 1913. (3078). 
Alaska peninsula, to Coronado Islands, Baja Cal., in deep 
water. 
21:0748 Genus Seila A. Adams. 
Shell spiral, elongated, many-whorled, frequently varicose; 
aperture channelled in front, with a less distinct canal posteriorly; 
outer lip not reflected, nuclear whorls sinistral; transversely 
lirate. 
21:0749 Seila montereyensis Bartsch. 565. 2715. 
Formerly called Cerithiopsis assimilata Cpr., and credited 
as from Monterey, Cal., to Panama. The Californian shell has 
been given the above name, as it is found to differ from the more 
southern species. It consists of 10 whorls, round which run 3 
strong spiral ridges, winding from the apex to the aperture. 
Length 11 mm, diameter 3. Dark brown. Rare at San Diego. 
It resembles a Bittium in general appearance, but easily recog- 
nized by the 3 spiral ridges. 
21:0750 Genus Serripes Beck, 1841. 
21:0751.Serripes groniandious Gmelin, 1792. 1064. 
Arctic Seas; Hakodate, Japan; Puget Sound. Circumboreal. 
21:0752 Serripes laperousei Deshayes, 1839. 1065. 
Bering Strait; Hakodate, Japan; Sitka, Alaska. 
21:0753 Genus Xylophaga Turton, 1822. 
Shell globular, with a transverse furrow; gaping in front, 
closed behind; pedal processes short and curved; anterior mar- 
gins reflected, covered by 2 small accessory valves; burrow oval, 
lined with shell. Animal included within the valves, except the 
Slender contractile siphons, which are furnished with pectinated 
ridges, and divided at end; foot thick, very extensile. 
21:0754 Xylophaga mexicana Dall, 1908. 
Monterey, Cal., to Acapulco, Mexico. X: dorsalis of West 
Coast lists (1188). 
aS SS 
