1914] 



Martin: New Species of Fossil Mollusca 



185 



Occurrence. — This species occurs quite abundantly in the Wildcat 

 Series on Eel River three-quarters of a mile north of Scotia, Hum- 

 boldt County, California. University of California Locality 1878. 



The faint spiral cords on the upper whorls of this species are very 

 similar to the sculpture on Chrysodomus tabulatus Baird, and sug- 

 gest that the two forms are closely related. The new species may be 

 distinguished from C. tabulatus by the much more elongate form, 

 much longer pillar and canal, more tabulated whorls, and almost 

 obsolete sculpture. 



Named in honor of Professor A. C. Lawson, who first described 

 the Wildcat Series. 



CHRYSODOMUS EUREKAENSIS, n. sp. 

 Plate 21, figures la and lb 



Shell large, thick, solid, with six to eight whorls which increase 

 rapidly in size; spire moderately high, one-third the length of the 

 shell ; whorls of the spire well rounded with greatest convexity cen- 

 tral, giving the whorls a bulging appearance ; uppermost whorls of 

 the spire ornamented with about four faint spiral lines which are 

 equidistant and separated by much broader interspaces ; lower whorls 

 of adult specimens smooth except for axial lines of growth ; whorls 

 constricted and concave in front of the suture, forming a poorly 

 defined collar or sutural band on the posterior portion ; anterior por- 

 tion slightly convex, sloping inward to the suture ; body-whorl large, 

 with greatest convexity above the middle uniformly tapering below ; 

 posterior portion concave, with distinct somewhat rogose collar; an- 

 terior portion long, nearly straight ; ornamentation consisting of lines 

 of growth which are particularly pronounced near the outer lip; 

 aperture elliptical ; outer lip thickened, arcuate posteriorly ; inner 

 lip slightly incrusted ; pillar long, twisted, with a broad anterior sulcus 

 paralleling the canal; canal long, recurved. 



Dimensions. — Length of the type specimen, spire defective, 

 86 mm. ; maximum diameter of the shell, 45 mm. ; length of the aper- 

 ture, 40 mm.; length of the canal, 16 mm. 



Occurrence. — The type and four other specimens, showing all 

 stages of development, were collected from the Wildcat Series on 

 Eel River near Scotia, Humboldt County, California. University of 

 California Locality 1878. 



