480 University of California Publications in Geology [Vol. 8 



Gastropoda 



ASTRALIUM RAYMOND I, A. sp. 

 Plate 65, figures 15 and 1 6 



Shell large ; spire elevated ; apex acute ; whorls gently convex, six 

 or seven in number; body whorl about equal in height to the spire; 

 base nearly flat; sutures appressed. Whorls highly ornamented; body 

 whorl sculptured by about twenty-two longitudinal, slightly oblique 

 ribs which reach from the suture down to about half the height of 

 the whorl ; between the base and the longitudinal ribbing are two 

 strong spiral rows of elongate, oblique nodes ; the nodes in each row 

 are opposite each other and alternate with and are equal in number 

 to the longitudinal ribs. Base sculptured by four heavy revolving 

 ribs which show a tendency to be nodose. Whorls of spire sculptured 

 similarly to body whorl, except that the lower of the two rows of 

 oblique nodes on each whorl is partially concealed by the whorl below ; 

 outer lip thin. Peristome nearly round, discontinuous; umbical tract 

 bounded by a broad, shallow groove. 



This species resembles rather closely in sculpturing and in outline 

 A. undosa Wood, a Eecent species on this coast. A. undosa has the two 

 rows of nodes near the base of each whorl, with a similar system of 

 longitudinal ribbing, but it differs in that the lower row of nodes is 

 more prominent and becomes so joined that they might be considered 

 as a nodose ridge rather than as a distinct row of nodes ; this lower 

 prominent nodose ridge gives a collardike effect to the lower part of 

 each whorl, which is not seen on A. raymondi, n. sp. On A. undosa 

 there is a node at the lower end of each longitudinal rib, not seen on 

 A. raymondi. The whorls of A. raymondi are more convex than on 

 A. undosa Wood, and the base of the body whorl is not so flat. 



Named in honor of Professor W. J. Raymond of the University of 

 Calif ornia. 



Dimensions. — Type specimen : height, about 32 mm. ; greatest width 

 of body whorl, 44 mm. 



Occurrence. — A very common species in the Upper San Pablo 

 Group above the Astrodapsis whitneyi zone; usually found associated 

 with Tivela gabbi, n. sp. 



