308 PROCEEDINGS OF THE NATIONAL MUSEUM. ^ol. 56. 



thin, with no internal denticulations; pillar with four plaits, including 

 the thickened edge, the two posterior plaits larger than the others; 

 general form not unlike that of eremus, but more slender; height of 

 shell, 3.5; of last whorl, 2.8; diameter, 1.6 mm. U. S. Nat. Mus. 

 Cat. No. 194986. 



Type-locality. — U. S. P'ish Commission station 2813, among tho 

 Galapagos Islands, in 40 fathoms, coral sand. 



HYALINA MYRMECOON, new species. 



Shell minute, white, smooth, polished, with about three whorls 

 forming a blunt spire, widest n.ear the posterior commissure of the 

 aperture, attenuated in front, sides moderately convex; suture ob- 

 scure; aperture r.arrow, outer lip straight, slightly thickened; body 

 with a w^ash of enamel, pillar with three plaits; height, 3.3 ; maximum 

 diameter, 1.6 mm. U. S. Nat. Mus. Cat. No. 9440. 



Type-locality. — San Diego, California (Brannan), Stearns Collec- 

 tion. 



Genus BOREOMELON Dall, 1918. 



Type.- — Scaplidla stearnsii Dall, 1872. 



The fortunate receipt of some ovicapsules of this species shows that 

 the larval specimens have a smooth, shelly nucleus, so that it must be 

 removed from the Caricellinae, to which it has hitherto l^een referred, 

 and placed under Fulgoraria in the Volutinae. In the absence of the 

 nuclear characters the writer formerly placed this species with 

 Adelomelon, though with some doubts. 



Genus PHENACOPTYGMA Dall. 1918. 



Shell fusiform, with transverse and axial sculpture, elongated canal 

 and apparently simple pillar; the axis in the upper whorls with two 

 well-marked plications. 



Type.—Surculina cortezi Dall, 1908. 



This shell has the appearance of a Pleurotomoid, with the whorl 

 constricted and appressed near the suture and a feeble mcurvation 

 of the margin of the lip at the constriction. By grindhig away a por- 

 tion of the apical whorls it was revealed that the axis is furnished 

 with plications which extend to the beginning of the penultimate 

 whorl. It is probably a member of the Volutidae, which family is 

 known to include several genera in which the plaits become obsolete 

 before reaching the apertm"e, or even, as in Halia, completely dis- 

 appear. 



STRIGATELLA (ATRIMITRA) CATALINAE, new species. 



Shell solid, black, fusiform, with about seven whorls exclusive of 

 the (lost) nucleus; suture depressed, not deep, the whorls only mod- 

 erately convex and polished; axial sculpture of extremely fine hardly 

 perceptible incremental lines; spiral sculpture of about four fine in- 



