156 



University of California Publications in Geology 



[Vol. 13 



This species differs from T. ponderosum Gabb 31 in that it possesses 

 a longer body whorl, longer canal, and a depression of the body whorl 

 near the base. 



T. daviesi, n. sp., resembles T. carisacnsis (Anderson) 32 in pos- 

 sessing the depression on the lower part of the body whorl, but in the 

 latter the depression is much more strongly developed and takes the 

 form of a groove. T. daviesi further differs from T. carisaensis in 

 that it is less solid, more slender, and less prominently nodose. 



TROPHON GRACILIS CLARKI, n. nom. 



Plate 6, figures 2, 3, and 4 



Troplwn gracilis pdbloensis. Clark, B. L., Univ. Calif. Publ. Bull. Dept. 

 Geol., vol. 8, p. 498, pi. 66, figs. 6 and 7, 1915. 



Type.— No. 11625; cotype— No. 11626; Briones cotype— No. 12390. 



"Shell medium-sized; spire rather high; apex acute; number of whorls to spire 

 five or six; body whorl large; sutures obscurely appressed. Whorls angulated, 

 with the narrow surface above the angulation sloping up gently to the suture. 

 Surface of shell crossed by ten or eleven prominent lamella-like varices which 

 are flexed forward and produced on the angle into upright, fairly prominent 

 spines; on the upper whorls of the spire the varices become prominent ridges. 

 Spiral ribbing lacking; outer lip sharp; inner lip smooth and incrusted; canal 

 broken on all specimens that the writer so far has obtained." 



Dimensions. — Clark's type, U. C. no. 11625; alt., unknown; max. width, 32 mm. 

 Clark's cotype, U. C. no. 11626; alt., unknown; max. width, 26 mm. Author's 

 cotype, IT. C. no. 12390; alt., 53.7 mm.; max. width, 30 mm.; alt. aperture, 

 33.6 mm. 



Occurrence. — Clark's type and cotype are from the Lower San PaMo, IT. C. 

 loc. no. 409. The writer's cotype is from the Briones, IT. C. loc. no. 177. 



Clark in this paper described two varieties of different species of 

 the genus Trophon, to both of which he ascribes the name "pablo- 

 ensis. " n. var. Hence to avoid duplication of terms, this variety has 

 been renamed in honor of Professor Clark. 



In one of the specimens in the Briones the canal has been preserved 

 and the following may be added to Clark 's description : Aperture 

 elongate ; canal moderately long and recurved ; umbilicus subperforate. 



This canal is very similar to that of Trophon gracilis (Perry), 33 

 and hence further shows the relationship of this variety to that species ; 

 but the differences noted by Clark in his description seem to be 

 sufficient to warrant making this form a distinct variety. 



si Gabb, op. cit., vol. 2, p, 2, pi. 1, fig. 3, 1869. 



32 Anderson, op. cit., p. 206, pi. XVII, figs. 90 and 91, 1905. 



33 Perry, Conch., pi. IX, fig. 4. 



