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University of California Publications in Geology [Vol. 8 



tinct; body-whorl large, slightly concave near the suture; posterior 

 half very convex; anterior half nearly flat; unsculptured except for 

 lines of growth ; aperture elliptical ; outer lip thick ; inner lip heavily 

 incrusted; canal long, defective in the type specimen. 



Dimensions. — Length of the type, 100 mm., the canal and apex 

 defective; maximum diameter of the shell, 50mm.: length of the 

 aperture, 45 mm. ; width of the aperture, 25 mm. ; apical angle, 28 

 degrees. 



Occurrence. — The type and one other specimen were obtained from 

 the Purisima Formation at Aho Nuevo Bay, San Mateo County, Cali- 

 fornia. University of California Locality 1780. 



The distinguishing characters of this species are : smooth whorls 

 except first few of the spire, absence of tabulation on the posterior 

 portion of each whorl, and slender form. It closely resembles Chry- 

 sodomus eurekacnsis, n. sp., from which it may be separated by its 

 more elongate form, lack of well-defined collar on the body-whorl, lack 

 of the bulging appearance of the whorls, and the smaller apical angle. 



CHRYSODOMUS TABULATUS var. COLMAENSIS, n. var. 

 Plate 20, figure 1 



Shell broadly fusiform, large, with seven or eight strongly tabu- 

 lated whorls ; spire moderately high, about one-fourth the total 

 length of the shell; whorls of the spire rounded, convex, sculptured 

 with spiral threads which alternate large and small, and axial lines 

 of growth ; on the penultimate whorl there are four or five coarse 

 spiral cords, between each of which there are three smaller spiral 

 threads, the middle one of whicli is more pronounced than those 

 on either side ; upper whorls of spire similarly sculptured ; tabulation 

 excavated or concave ; point of angulation raised, forming a pro- 

 nounced carina ; surface of tabulation ornamented with very fine 

 spiral threads ; suture impressed ; body-whorl very large, broadly 

 rounded, convex, sculpture the same as the whorls of the spire, most 

 pronounced on the anterior portion ; aperture ovate ; outer lip slightly 

 reflexed; inner lip incrusted; canal moderately long, recurved. 



Dimensions. — Altitude of figured specimen, apex defective, 112 

 mm. ; width of body-whorl, 55 mm. ; length of the aperture, 50 mm. 



Occurrence. — This variety is not uncommon in the Merced Series 

 south of San Francisco. University of California Locality 1736. 



