1916] 



Dickerson: Tejon Eocene of California 



497 



NYCTILOCHUS DIEGOBNSIS (Gabb) 



Plate 41, figures 6a, 6b 



Tritonium diegoensis Gabb, Geological Survey of California, Palaeon- 

 tology, vol. 1, p. 95, 1864. 



This species occurs in the Tejon of Oroville South Table Mountain. 

 Several specimens exhibit the aperture and the canal far better than 

 Gabb's type. The canal is very short and narrow and the outer lip 

 is thickened and denticulated. In the type the canal and aperture 

 are obscured by the rock matrix. 



PERISSOLAX GABBI, n. sp. 

 Plate 37, figure 14 



Shell thick, spire moderately high ( ? ) , body-whorl prodoundly 

 angulated at a point one-third of its length from the posterior ; suture 

 distinct ; portion of whorl above shoulder slightly convex and nearly 

 at right angles to the axis ; body-whorl decorated by very prominent 

 axial ribs which extend from the suture over the entire whorl. These 

 ribs have flat-pointed nodes at the shoulder and are nearly obsolete at 

 either end. Revolving lines of moderate size with minute interlacing 

 riblets cover the entire shell. These lines are crossed by fine growth lines 

 which give portions of the surface a reticulated appearance. Four or 

 five of these revolving lines are found above the shoulder of the body- 

 whorl. Mouth quadrate ; outer lip simple and divided in thirds by 

 two angulations ; inner lip slightly incrusted ; canal long and nearly 

 straight. 



It appears to be a descendant of Parissolax brevirostris Gabb of 

 the Chico (Cretaceous), to which it bears a striking resemblance. 

 P. brevirostris has three distinct angulations on outer lip and a 

 rounded body-whorl, while P. gabbi has only two angulations on outer 

 lip and a decidedly angular body-whorl. P. gabbi is also less robust. 

 The genus Perissolax resembles Tudicla of the eastern Eocene in gen- 

 eral appearance. They both appear to belong to the Pulguridae 

 rather than to the Pusidae as Gabb suggested. 



Named in honor of W. M. Gabb, who laid the foundation of 

 palaeontology on the Pacific Coast. 



Dimensions. — Length of broken specimen, 25 mm. ; width of body- 

 whorl, 14 mm. 



Occurrence. — The specimen figured was found at University of 

 California Locality 532, Solen Stantoni Zone, where it was asso- 

 ciated with Solen stantoni Weaver and Thracia harquinesensis Weaver. 



