NO. 12 STRONG AND HERTLEIN: MARINE MOLLUSKS 207 



Odostomia (Pyrgulina) marginata C. B. Adams, Dall & Bartsch, U. S. 

 Nat. Mus., Bull. 68, 1909, p. 169, pi. 18, figs. 5, 5a. Adams' 

 specimen from Panama figured. 



Hypotype: No. 737 (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. Twenty-five specimens from Loc. 

 27,229 (C.A.S.), were dredged in Bahia Honda, Panama, and 4 speci- 

 mens were dredged at Loc. 27,228 (C.A.S.), off Taboga Island, 

 Panama. 



Our specimens do not agree in all particulars with the description 

 and figure given by Dall and Bartsch from 1 of the 2 specimens col- 

 lected by C. B. Adams. Neither does the description by Dall and 

 Bartsch agree entirely with that of Adams. They state that the axis 

 of the nuclear whorls is at right angles to that of the following whorls ; 

 Adams states "with the apex oblique," as is the case in our specimens. 

 Dall and Bartsch state 14 axial ribs, Adams 11 or 12, while our speci- 

 mens show from 16 to 24. However, these specimens come from the 

 type locality of the species and agree in other ways with both descrip- 

 tions. It would seem reasonable to suppose that they represent the 

 normal form of the species better than the 2 specimens collected by 

 Adams. 



Odostomia (Mlralda) azteca Strong & Hertlein, new species 



Plate 18, Fig. 10 



Shell minute, elongate-ovate, translucent white; nuclear whorls 

 deeply obliquely immersed in the first postnuclear whorl; postnuclear 

 whorls 5, sutures channeled; sculptured with 2 strong, elevated, nodu- 

 lous, spiral cords, one at the summit and the other on the middle of 

 the whorl; of the nodules 18 appear on the second, 20 on the third, and 

 22 on the penultimate whorl on each cord ; the nodules on the lower 

 cord are rounded, while those on the upper cord are axially elongate; 

 the interspaces between the 2 cords and between the lower cord and 

 the suture are marked with feeble axial riblets corresponding in posi- 

 tion to the nodules; peripheiy of the last whorl marked by a smooth 

 cord separated from the lower nodulous cord by a groove a little nar- 

 rower than that between the 2 nodulous cords; on the base below the 

 peripheral cord are 2 similar but smaller spiral cords; aperture ovate, 

 the edge of the outer lip broken in the type; columella strong, curved, 

 with an obscure fold at its insertion. The type measures: length, 1.3 

 mm; diameter, 0.8 mm. 



