— 53 — 



MIOCENE AND PLIOCENE (OR NEOCENE) FOSSILS. 



Agasoma Gabb. — This group of species, although not very well 

 defined, and made by its author to include very dissimilar forms, seems 

 to be a good division of what might otherwise be retained in Purpura. 

 I propose to add a species, and a sub-genus with another species, possi- 

 bly however, of diflerent affinities. 



Agasoma barkerianum n. sp. (PL V, Fig. 63.) 



Pyriform, nuclear whorls immersed, smooth, next five ornamented by 

 eighteen to thirty-six vertical riblets, crossed by three to eight revolving 

 ridges, giving them a closely beaded surface. On the sixth whorl the 

 vertical are more distant, and change into blunt tubercles at the suture, 

 ten such forming a serrated crown. On the body-whorl this is stronger, 

 forming a series of sharp folds turned back at irregular intervals (which 

 were posterior notches as the mouth grew), and varices running forward 

 from each to the canal, about fifteen in number. The tubercles of the 

 fifth whorl continue in a row around middle of body-whorl, making 

 an angle at each varix. Two other ridges cross the anterior third of 

 dorsum to the end of beak. The whole of the fifth and body whorls 

 are also traversed by fine ridges, both vertical and revolving, forming a 

 fine cancellation, less strong than on the spire. Mouth simple, oval; 

 length, 1.75 inch; breadth, 1.15; mouth, 1.25; width, 0.50; canal, 0.24 

 wide. 



This species much resembles a cast figured in Prof. Blake's report 

 (Pac. R. R. Rept., vol. V, foss. pi. VII, f. 63), except in the canal, given 

 there as straight, and that may perhaps rather be A. gravida Gabb, as 

 suggested by him. Fig. 66 resembles the dorsal varices of my species, 

 which are like those often found on Purpura crispata. Only two speci- 

 mens found, on John Barker's ranch, Kern County. 



TROPHOSYCON nov. subg. 



General form fig-shaped, with a strongly twisted canal; suture i:)lain, 

 no posterior notch. This shell is perhaps as nearly allied to the 

 Fulgurs of the east coast as to Agasoma, and two fossil species of Florida 

 have a similar double row of knobs, but in the canal it is very unlike 

 them. 



Agasoma? (Trophosycon) kernianum n. sp. (PI. Ill, Fig. 52.) 



Shell pyriform, spire very short, first two whorls smooth (eroded), 

 next two lightly sculptured, with revolving ridges from sixteen on the 

 third, to eleven on the upper surface of fourth. A row of about nine 

 prominent vertical tubercles around posterior angle of body-whorl, and 

 seven alternating with them around lower angle, the interval nearly 

 5f 



