MUSEUM OF COMPAI^ATIVE ZOOLOGY. 353 



None of our si)ecinieii8 li;ivc the Ijody wlioil smooth like tlie Challenger 

 specimen, and none are (^uite so pointed as Watson's figure. Still, I have very 

 little doubt that his is an abnormally smooth specimen of the same species as 

 that which I have calh'd allndn. If they are <listinct, ours will be LeptotJiyra 

 albida, and his Lcptothijra induta; for there cannot be a shadow of a doubt that 

 they all belong to the group of L. sangxiinea, I have not been able, of course, 

 to coni]mre specimens 



The fact of the existence of the group, apparently abundant, in deep water, 

 and the other fact of the wide distribution of the shallow-water types of the 

 genus, are points which march together in this case as in many others, and 

 have an obvious significance. 



'O* 



Leptothyra Philipiana n. s. 



Plate XXIV. Fiffs. 7. 7 a. 



Shell whitish, of four rounded whorls and a minute smooth nucleus; rather 

 depressed, base rounding into the rest of the whorl. Sculpture of ten even 

 strong spiral costse, with channelled interspaces, here and. there toward the 

 aperture indications of intercalary hardly raised spirals, and over all faint 

 spiral strioe more or less visible under a lens. Eadiating sculpture faint, the 

 tops of the spirals are a little undulated, and two close to the umbilicus are 

 indistinctly nodulous, otherwise there are only the usual incremental lines. 

 Operculum as usual ; umbilicus perforate, rather profound ; aperture prolonged 

 above, edges a little flaring, subcircular. Alt. 3.5, diam. 4.0 mm. 



Habitat. Station 192, near Dominica, in 138 fms., bottom temperature 

 63°.0 F. 



This shell may not be quite adult, and the umbilicus may be closed later. 

 It has a different shape from any of the varieties of the preceding which have 

 come under my notice, and is much smaller. 



Leptothyra Linnei n. s. 



Plate XXXIII. Fig. 9. 



Shell small, white, solid, elevated, blunt, with five well rounded whorls; 

 spiral sculpture of about sixteen even rounded costse, separated by wider in- 

 terspaces, with an occasional intercalary thread ; the two nearest the suture are 

 generally more or less beaded by the radiating sculpture, the rest usually 

 plain; spiral sculpture of close oblique radiating lines coincident with the 

 lines of growth, with at regular intervals more emphasized depressions which 

 nodulate the upper spirals and in rare instances are produced all over the 

 shell ; the costse are more or less nodulated or even imbricated at the inter- 

 sections, so that in extreme cases (var. limata) the shell is as rough as a file 

 all over; base full and rounded, umbilical depression or perforation occasionally 

 present in llie young, wholly absent in the adult; aperture rounded, the ujiper 



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