AHT.18 SMALL SHELLS DEEDGED BY '' ALBATROSS *' BALL 49 



intersections with the ribs and a little closer set on the canal ; there 

 is a small constriction dividing the first three threads in front of the 

 suture from those succeeding them; aperture sublunate, outer lip 

 thin (not mature), body erased, pillar with three plaits, canal straight, 

 as long as the aperture; axis not pervious. Length of shell 11; of 

 aperture and canal, 6; diameter, 5.5 mm. U. S. Nat. Mus. Cat. 

 No. 108440. 



Off Georgia and Fernandina, not rare. 



Near to M. styria Dall, but has more sharply cut ribs and the 

 sculpture is not so regularly reticulate. 



MITRA ZILPHA, new species 



Shell small, dull white, fusiform, with a large smooth white nucleus 

 of a whorl and a half and three and a half subsequent whorls; suture 

 distinct, whorls moderately rounded, sometimes with a shoulder in 

 front of the suture; axial sculpture of a variable number of rounded 

 strong ribs (14 to 21 on the last whorl) with interspaces wider or 

 narrower in conformity with the number of ribs, extending over the 

 whorls but obsolete near the canal; spiral sculpture of fine threads, 

 three or four on the penultimate and 10 or more on the last whorl, 

 with wider interspaces, overrunning but not nodulating the ribs; 

 aperture semilunate, narrow, outer lip thin, smooth within, the body 

 smooth, the pillar straight, with two rather strong oblique plaits; 

 canal produced, axis minutely pervious. Length of shell, 6; of aper- 

 ture and canal, 3; diameter, 3 mm. U. S. Nat. Mus. Cat. No. 107971. 



Off Georgia and Fernandina, 16 specimens. 



MITRA HENDERSONI, new species 



Shell small, of about seven whorls exclusive of about three small 

 smooth brownish nuclear whorls, color whitish with a brownish base 

 darker near the periphery, which appears as a narrow brown band 

 just behind the suture on the spire; axial sculpture of (on the last 

 whorl about 10) rather sharp, nearly vertical ribs with wider inter- 

 spaces, obsolete near the canal; spiral sculpture of (on the penulti- 

 mate whorl about eight) rather feeble flattish threads stronger and 

 more widely spaced toward the canal from which they are separated by 

 a distinct sulcus; the canal carries two or three much stronger spiral 

 threads; the periostracum ispale and fibrous; the suture distinct but 

 not deep; aperture narrow, the outer lip sharp, lirate internally, the 

 pillar with three plaits, the canal moderately dift'erentiated, slightly 

 recurved. Length of shell, 17; of last whorl, 10; max. diameter, 6 

 mm. U. S. Nat. Mus. Cat. No. 333435. 



Off Georgia, one specimen with hermit crab. 



