NO. 12 STRONG AND HERTLEIN : MARINE MOLLUSKS 239 



Cyclostrema mccullochae Strong & Hertlein, new species 



Plate 21, Figs. 8, 10, 11 



Shell minute, depressed, semitransparent ; nuclear whorls nearly 2, 

 smooth, rounded, the apex slightly elevated; postnuclear whorls 2; 

 spiral sculpture of 7 cords, of which the first is situated immediately 

 below the impressed suture, the second is on the middle of the upper 

 surface of the whorls, the third forms a sharply angulated shoulder to 

 the whorls, the fourth is on the periphery, the fifth sharply angulates 

 the base, the sixth bounds the broadly open umbilicus, and the seventh 

 is on the middle of the umbilical wall; of these cords the third and fifth 

 bound a nearly square peripheral area on the first half of the body whorl, 

 but as the second, third, and fourth cords grow successively weaker on 

 the last half of the body whorl and disappear before the lip is reached, 

 this part of the last whorl becomes rounded; the first, fifth, and sixth 

 cords increase rather than diminish with age; axial sculpture of rather 

 close, regularly spaced, retractive riblets which appear on the entire 

 surface except on the latter part of the body whorl where they fade 

 out in the same manner as the spiral cords; the junction of the spiral 

 cords and axial ribs slightly nodulous; aperture nearly circular, outer 

 lip fairly thick, slightly undulated by the ends of the fifth and sixth 

 spiral cords ; inner lip strongly curved, with a heavy callus over the body 

 of the shell spanning the third, fourth, and fifth spiral cords. The type 

 measures: greater diameter, 1.1 mm; height, 0.5 mm. 



Holotype: No. 716 (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. Eighty-five additional specimens were 

 dredged at the same locality. 



This species comes nearer to Cyclostrema ada/nsi Bartsch^'* than to 

 any other species described from the west coast. It differs in the arrange- 

 ment of the spiral cords and in the less distinct sculpture. "Vitrinella" 

 concinna C. B. Adams*^^ would also appear from the description to be 

 quite similar but it is said to be a larger shell with 5 spiral cords. 



This species is named for Dr. Irene McCulloch of the Department 

 of Zoology of The University of Southern California. 



64 Cyclostrema adamsi Bartsch, Proc. U. S. Nat. Mus., vol. 39, January 9, 

 1911, p. 231, pi. 39, figs. 4, 5, 6. "Panama." 



6 5 Vitrinella concinna C. B. Adams, Ann. Lyceum Nat. Hist. New York, 

 vol. 5, 1852, pp. 408 (No. 258), 539. "Panama." 



