40 PROCEEDINGS OP THE NATIONAL MUSEUM vol.70 



MANGILIA ? PERCOMPACTA, new species 



Shell minute, solid, whitish, the nucleus lost, but three and a half 

 subsequent whorls remain; suture distinct, constricted, with a fringe 

 of minute axial wrinkles on the fasciole in front of it; there is no 

 other axial sculpture except faint incremental lines; spiral sculpture 

 of (on the last whorl about 10) fine, equal and equally distributed 

 low threads with narrower interspaces, covering the whole shell except 

 the anal fasciole; aperture ample, hardly differentiated from the short 

 canal; anal sulcus wide and rather deep; outer hp prominently 

 arcuate; pillar short, twisted, strong; axis minutely pervious. Length, 

 2.3; diameter, 1.3 mm. U. S. Nat. Mus. Cat. No. 108301. 



One specimen off Georgia. 



This is perhaps not a Mangilia but may be tentatively placed here in 

 the absence of a knowledge of the animal. The only other species 

 which approaches it in form which I have been able to discover is 

 the much larger " DapJinella" nana Loven. 



MANGILIA? ACLONETA Dall 



Drilliai? dalli Verrill, var.) acloneta Dall, Bull. Mus. Comp. Zool., vol. 18, 

 p. 92, June, 1889. 



This is much smaller when adult than the typical dalli. It occiu-s 

 abundantly at both stations 2415 and 2668, and was also obtained 

 off Martinique, in 170 fathoms. 



The typical acloneta is smooth, but has occasionally a slight angle 

 at the shoulder and a few obscure riblets on the earher whorls. 

 U. S. Nat. Mus. Cat. No. 87332. 



Another form which is probably an extreme variety of acloneta, 

 has a strong shoulder angle, the obsolete ribbing is carried on over all 

 the whorls and the base is spirally threaded. This was named at the 

 same time as acloneta, variety cestrota. A single specimen was ob- 

 tained off Fernandina; U. S. Nat. Mus. Cat. No. 107935. 



Variety cestrota was also obtained at station 2399, in 196 fathoms, 

 mud, temperature 51.6°, in the Gulf of Mexico, between the delta of 

 the Mississippi and Cedar Keys, Florida, by the U. S. S. Blake. 



MANGILIA? CRATERA, new species 



Shell small, white, solid, nearly smooth with a large smooth nucleus 

 of about two whorls and four and a half subsequent whorls; suture 

 distinct, not appressed, the fasciole in front of it obscure, not con- 

 stricted; the only sculpture on typical specimens consists of feeble in- 

 cremental lines; there are faint indications of ribbing on some of the 

 worn specimens which may belong to this species; whorls well rounded 

 and rather rapidly increasing in diameter; aperture ample, anal sulcus 

 wide and shallow; outer lip slightly thickened and inflected; canal 

 wide, hardly differentiated; pillar short and strong, the axis imper- 

 vious. Length, 8.5; diameter, 4 mm. U. S. Nat. Mus. Cat. No. 107946. 



