Clark: The San Lorenzo Series of Middle California 169 



JV. recluziana andersoni differs from the typical JV. recluziana in 

 that the body whorl is broader posteriorly, the sides of the whorl being 

 more nearly perpendicular to the base, and Hatter; also, in the pres- 

 ence of the subtabulate, depressed area just below the suture. On 

 most of the specimens examined, the callus does not seem to be so 

 heavy posteriorly as on the typical JV. recluziana. In other respects 

 the two species are very similar. 



JV. recluziana andersoni is apparently a direct offshoot of JV. reclu- 

 ziana or vice versa, both appearing - first in the Oligocene ; during 

 Lower and Middle Miocene times it apparently became a distinct form, 

 for in these horizons the typical JV. recluziana is very scarce ; possibly 

 during this time the two lived in different environments. The typical 

 JV. recluziana has continued to live up to the present day, the other 

 form having become extinct. 



JV. recluziana andersoni may be the same as Conrad's species, JV. 

 ocoyana, which comes from Ocoya Creek, California, where it is asso- 

 ciated with a typical Monterey fauna. Conrad's description is very 

 meagre and his figures poor, so much so that it is impossible to make 

 a specific determination from them. The fact that there are at least 

 two species of Natica in the fauna from Ocoya Creek beds would make 

 it unsafe to determine this species as JV. ocoyana on the basis that the 

 type came from the same horizon. W. H. Dall lists JV. ocoyana as a 

 questionable synonym of JV. inezana, the type of which came from 

 the San Inez Mountains, California. Certainly JV. recluziana ander- 

 soni 1 ™ is not the same as what Dall has determined as JV. inezana 

 from Coos Bay, Oregon. He says of this form: "The shell from the 

 Miocene of Coos Bay, which I have referred to JV. inezana, however, 

 has the open part of the umbilicus behind the umbilical and to the 

 left of it, with no dividing sulcus, and by these characters can be 

 recognized at a glance." The umbilical opening, when present on 

 JV. recluziana andersoni, as on JV. recluziana, is always anterior to the 

 callus. 



Genus SINUM Bolten 

 SINUM SCOPULOSUM Conrad 

 Plate 22, figure 8 



Sigarctus scojmlosus Conrad, U. S. Exp]. Exp., Geol., Appendix, p. 727, 



pi. 19, fig?. 6, 6a only, 1849. 

 Catinus scopulosus Conrad, Amer. Jour. Coneh., vol. 1, p. 151, 1865. 



i3» For discussion by Dall, see U. S. Geol. Surv., Prof, paper no. 59, p. 88, 

 1909. 



