NO. 12 STRONG AND HERTLEIN : MARINE MOLLUSKS 243 



nearly circular, very oblique, outer lip fairly thick; inner lip thick, 

 strongly curved, with a strong callus over the body of the shell. The 

 type measures: greater diameter, 1.0 mm; height, 0.4 mm. 



Holotype: No. 721 (Calif. Acad. Sci. Paleo. Type Coll.), from 

 Loc. 27,229 (C.A.S.), dredged in from 3 to 9 fms. in Bahia Honda, 

 Panama. L. G. Hertlein collector. Nine additional specimens were 

 dredged at the same locality and 8 specimens dredged of^f Taboga Island, 

 Panama. 



This species appears to be quite similar in shape and sculpture to 

 "Circulus" rossellinus Dall,"^ described from San Diego, California, 

 but it is only half the size. The closing over of the umbilicus is some- 

 what like that in the genus Teinostonia but there is no defined callus 

 pad or tongue, simply a change in the shape of the last whorl. 



This species is named for Dr. G. Dallas Hanna, Curator of the 

 Department of Paleontology of the California Academy of Sciences. 



Delphinoidea hambachi Strong & Hertlein, new species 



Plate 22, Figs. 8, 9, 10 



Shell small, depressed, semitransparent ; nuclear whorls 2^^, smooth, 

 well rounded, with the apex slightly elevated; postnuclear whorls 2]/^, 

 slightly rounded, sutures closely appressed; spiral sculpture on the first 

 whorl of 6 raised threads Vv^hich gradually increase in number but di- 

 minish in strength until on the last whorl they can hardly be distin- 

 guished; these are crossed by still finer lines of growth which give the 

 threads a granular and the interspaces a pitted appearance under the 

 microscope; peripheiy of the last whorl well rounded; base slightly 

 rounded, umbilicus small, deep, more or less constricted by an expansion 

 of the body whorl back of the base of the inner lip; aperture nearly 

 circular, the posterior angle falling at the upper edge of the rounded 

 periphery, outer lip fairly thick; inner lip greatly thickened, strongly 

 curved, with a moderate callus over the body of the shell. The type 

 measures: greater diameter, 3.2 mm; height, 0.7 mm. 



Holotype: No. 720 (Calif. Acad. Sci. Paleo. Type Coll.), from 

 Loc. 27,228 (C.A.S.), dredged in from 3 to 9 fms. ofiE Taboga Island, 

 Panama. L. G. Hertlein collector. A second adult and 3 young speci- 

 mens were dredged at the same locality. 



70 f Circulus rossellinus Dall, Proc. U. S. Nat. Mus., vol. 56, August 30, 

 1919, p. 368. "Off South Coronado Island, near San Diego, California, collected 

 by Dr. Fred Baker, in three fathoms." 



