186 University of California Publications in Geology [Vol. 8 



There is considerable difference between the young and the old 

 forms of this species. The young specimens show well-developed spiral 

 sculpture on the spire and partly obscured spiral lines on the body- 

 whorl, while the adult specimens show spiral sculpture on the upper- 

 most whorls only. 



The characters which permit the separation of this species from 

 other California Chrysodomus forms are : the absence of a tabulation, 

 the absence of spiral sculpture on the lower whorls, the presence of a 

 well-defined sutural collar on the body-whorl, and the bulging appear- 

 ance of the whorls. 



CHRYSODOMUS SCOTIAENSIS, n. sp. 

 Plate 20, figures 3a and 3b 



Shell thin, large, elongate, with about eight whorls ; spire elevated, 

 with an acute apex ; whorls tabulated, almost uniformly rounded from 

 the shoulder of the tabulation to the suture below, sculptured with 

 thread-like revolving grooves and axial lines of growth; four or five 

 revolving grooves on the whorls of the spire and ten to twelve on the 

 body-whorl ; the grooves are about equally spaced over the surface of 

 each whorl but are most pronounced on the anterior portion ; inter- 

 spaces between the grooves having a width of three to four millimeters 

 ^>n the body-whorl and proportionally narrower on the whorls of the 

 spire ; tabulation narrow, not deeply excavated, and at right angles to 

 the axis of the shell ; suture impressed, distinct ; aperture ovate ; outer 

 lip thickened, reflexed, semicircular in shape, somewhat effuse, inner 

 lip incrusted, smooth ; canal short, recurved. 



Dimensions. — Length of the type specimen, apex and canal slight- 

 ly defective, 117 mm. ; maximum diameter of the shell, 55 mm. ; length 

 of the aperture, 55 mm. ; greatest width of the aperture, 28 mm. 



Occurrence. — Two specimens of this species were obtained from 

 the Wildcat Series on Eel River, three-quarters of a mile north of 

 Scotia, Humboldt County, California. University of California 

 Locality 1878. 



CHRYSODOMUS ANDERSONI, n. sp. 

 Plate 19, figure 4 



Shell large, thick, broadly fusiform, with about eight spirally 

 sculptured whorls ; spire elevated, about one-third the length of the 

 shell ; apex subacute ; whorls of the spire flattened, angulated about 



