NO. 12 STRONG AND HERTLEIN : MARINE MOLLUSKS 235 



Neither the figure nor description shows the 2 strong spiral cords, 

 one forming a bridge connecting the cusps at the posterior end of the 

 axial ribs and the other near the base of the whorls, shown on our 

 specimen. 



Megalomphalus hancocki Strong & Hertlein, new species 



Plate 23, Figs. 1-4 



Shell small, depressed, white; nuclear whorls about 2, very small, 

 smooth, glossy, brownish, forming an elevated, globular apex; post- 

 nuclear whorls nearly 3, rapidly enlarging, inflated, well rounded above, 

 with a distinct suture, below with a wide funicular umbilicus, bounded 

 by an obscure angle; entire surface sculptured with sharp, close-spaced, 

 incremental threads and finer, closer-spaced spiral threads, which are 

 most prominent in the interspaces; aperture semilunate, very oblique; 

 outer lip thin, flaring; columella slender, nearly straight, the upper end 

 expanded into a short, thin callus which renders the peritreme complete. 

 The type measures: greater diameter, 2.13 mm; lesser diameter, 1.81 

 mm; height, 1.0 mm. 



Holotype: No. 731 (Calif. Acad. Sci. Paleo. Type Coll.), from 

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

 Panama. L. G. Hertlein collector. Four much smaller, young specimens 

 were dredged off Taboga Island, Panama. 



The sculpture of this species is quite similar to that of Megalom- 

 phalus californiciis DalP^ from the Santa Barbara Islands, California, 

 but that is a much more elevated shell. Megalomphalus occidentalis 

 Bartsch,^*' the only other west coast species placed in the genus, is also 

 a more elevated shell with much finer sculpture. Megalomphalus souver- 

 biei De Folin^^ has a smaller umbilicus and a groove on the top of the 

 body whorl just below the suture, whereas the new species has a larger 

 umbilicus and lacks the groove in the body whorl. 



^^Macromphalina californica Dall, Proc. Biol. Soc. Washington, vol. 16, 

 December 31, 1903, p. 175. Santa Barbara Channel, California. 



Megalomphalus californiciis Dall, U. S. Nat. Mus., Bull. 112, 1921, p. 166, 

 pi. 14, fig. 7. "Santa Barbara Islands." 



^^ Macromphalina occidentalis Bartsch, Proc. U. S. Nat. Mus., vol. 32, 

 March 12, 1907, p. 233, text figs, a and b. Type locality, "Point Abreojos, Lower 

 California." 



'^'^ SigareUis sowverbiei De Folin, Les Meleagrinicoles (Havre), 1867, p. 

 68, pi. 6, figs. 8 and 9. On p. 9 it was stated that the shells described in the 

 volume came from "I'Ocean pacifique," "aux environs des Negritos" and "autour 

 des lies aux Perles, dans la baie de Panama." 



