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NO. 2193. WEST AMERICAN MARINE M0LLUSE8—BARTSCH. 675 



sculpture; the spaces inclosed between them are very shallow, rec- 

 tangular pits. In addition to the above sculpture the entire surface 

 of the spire and base is marked by many very slender lines of growth 

 and exceedingly fine microscopic spiral striations, the combination 

 of which gives the surface a somewhat cloth-like texture. Suture 

 strongly constricted; it would be channeled were it not for the fact 

 that the peripheral keel makes its appearance above the summit of 

 the whorl, hence removes the strongly channeled element. Periphery 

 of the last whorl marked by strong spiral cord, which is about as far 

 anterior to the fifth cord of the spire as that is separated from the 

 fourth. Base very short, decidedly concave, marked by three slender 

 spiral cords, of which the first is about as far anterior to the pe- 

 riphery as that is distant from the fifth cord on the spire. The other 

 two cords are very slender, the first being at the base of the columella, 

 while the next is a little distance posterior to it. Aperture subquad- 

 rate; quite strongly channeled anteriorly; the junction of the outer 

 and basal lip forming almost a right angle ; posterior angle obtuse ; 

 outer lip very thin, showing the external sculpture within and ren- 

 dered sinuous by the external sculpture at the edge; inner lip de- 

 cidedly oblique, slightly curved, slender, reflected and appressed to 

 the base ; parietal wall covered by a thin callus. 



The type, Cat. No. 168753, U.S.N.M., was collected by Miss 

 Challis off San Juan Island, Gulf of Georgia, British Columbia. 

 It has lost the nuclear turns; 7| postnuelear whorls remaining 

 measure — length, 11 mm. ; diameter, 3.8 mm. 



BITTIUM SERRA, new species. 



Plate 47, fig. 1. 



Shell stout, broadly conic, grayish white. Nuclear whorls de- 

 collated. Postnuelear whorls appressed at the summit, strongly 

 rounded, marked by slender, rounded, somewhat retractive axial 

 ribs, of which 18 occur upon the first and second, 20 upon the third, 

 22 upon the fourth, and 24 upon the remaining turns. In addition 

 to the axial sculpture, the whorls are marked by four spiral cords, of 

 which the first, which is at the summit, is a little weaker than the rest. 

 The junction of these cords w^ith the axial ribs form prominent, 

 strongly rounded tubercles, while the spaces inclosed between them 

 are rounded pits. Suture moderately constricted but not channeled. 

 Periphery of the last whorl rendered angulated by a spiral cord. 

 Base short, slightly concave, marked by four very low, broad, almost 

 equal, spiral cords, which are separated by mere impressed lines. 

 Aperture oval, narrowly, twistedly channeled anteriorly; posterior 

 angle obtuse; outer lip rendered wavy by the external sculpture; 

 inner lip decidedly curved, somewhat revolute, reflected over and ap- 

 pressed to the base ; parietal wall covered with a thin callus. 



