NO. 1574. WEST AMERICAN PYRAMIDELLID.E—DALL AND BARTSCH. 511 



the eleventh, and 30 upon the penultimate whorl. Intercostal spaces 

 not deeply depressed, about as wide as the ribs, ornamented by about 

 12 to 15 irreg-ularly spaced spiral striations between the sutures; those 

 near the summit of the whorls are closer and more feeble than those 

 near the periphery of the whorls. Sutures strongly impressed, some- 

 what wavy. Periphery of the last whorl somewhat angulated in 

 young specimens, moderately well rounded in adults. Base rather 

 short, marked by faint continuations of the axial ribs and faint wavy 

 spiral striation. Aperture subrhombic, posterior angle ol)tuse, outer 

 lip thin, showing the external sculpture and banding within; columella 

 stout, slightly twisted and rQvolute, provided with an ol)Iique internal 

 fold. The color markings in the specimen here described and figured 

 consist of a pale yellowish-brown band, about a quarter of the width 

 of the whorl between the sutures, covering the posterior part, fol- 

 lowed by a narrowband of the yellowish-white ground color, which is 

 followed by a band of brown a little darker than the tirst and about as 

 wide as the last-named white band; then a broad pale white l)and, 

 lastly a narrow pale yellow one above the periphery finishes the mark- 

 ing between the sutures. The periphery is marked by a narrow band 

 of white followed by a deep brown one which shades gradually to the 

 white about the umbilical region. 



The characters which ally this species to Morn tula are only feebly 

 developed, now and then two ribs become fused and suggest a varix; 

 the internal lirations, too, are only very feebly expressed and appear in 

 the aperture of only one specimen. The specimen figured has 14 post- 

 nuclear whorls and measures: Length 20.8 mm., diameter 5.1 mm.; it 

 was collected in 12 fathoms at Sitka Harbor, Alaska, and is Cat. No. 

 160192, U.S.N.M. No. 160069, U.S.N.M., contains individuals from 

 the same locality; No. 133231, U.S.N.M., has 2 from Port Orchard, 

 Washington, and No. 4180, U.S.N.M., 1 from Puget Sound, Wash- 

 ington. Seven specimens were collected by Rev. G. W. Taylor at 

 Banks Island, British Columbia. One of these, a young individual, 

 Cat. No. 196234, U.S.N.M., has furnished the description of the 

 nucleus. It has 9 post-nuclear whorls and measures: Length 5.2 mm., 

 diameter 2.1 nun. 



This is the largest species known from the west coast of America. 



TURBONILLA (MORMULA) TRIDENTATA Carpenter. 



Plate XLV, fig. 9. 



ChemnHzia tridentata Carpenter, Jour, de Conch., XIII (3d ser., V), 1865, p. 147. — 

 Turbonilla {Lancea) tridentata Dall and Bartsch, Mem. Cala. Acad., Ill, 

 p. 2713, 190;^, pi. II, figs. 1, la. 



Shell large, broad; chestnut colored, obscurely banded; nuclear 

 whorls three, helicoid, about one-third immersed, scarcely extending 

 beyond the margin of the spire, their axis being at a right angle to the 



