342 BULLETIN : MUSEUM OF COMPARATIVE ZOiJLOGY. 



This is a commou aud variable species from the Gulf of California to the 

 Galapagos Islands. 



tEPTOTHYRA Carpenter. 



LeptotKi/ra (Carpenter Ms.) Dall, Amer. Journ. Concli., 1871, 7, p. 130; type, 



Turbo sanguineus L. New name for Leptonyx Carpenter, preoccupied in 



vertebrates. 

 Leptonyx Carpenter and Adams, Proc. Cal. Acad. Sci., 1864, 3, p. 175; not of Gray, 



1837. 

 Collonia Pliilippi, Handb. Conch., 1853, p. 206; not of Gray, 1852. 

 Cantrainea Jeffreys, P. Z. S. Lond., 1883, p. 109; type, Trochus peloritanus Can- 



traine; Monterosato, Nom Conch. Medit., 1884, p. 49. 

 Cantraineia Fischer, Man. de Conch., 1885, p. 812. 

 Homalopoma Carpenter, Suppl. Rept. Brit. Assoc, 1863, pp. 588, 627, olim. for 



Turbo sanguineus Linne; name not validated, and withdrawn by Carpenter 



as preoccupied in Zoology. 



The shell wluch Carpenter regarded as the Turl/o sanguineus of Linne and 

 upon which his genus was really based, is described by Pilsbry as a distinct (Cali- 

 fornian) species under the name of Leptothyra carpenteri. 



The Anadema caelata A. Adams was regarded as a subgenus of Omphalius by 

 H. and A. Adams in 185i4, but is considered to be a Leptothyra by Pilsbry. It 

 has a very peculiar ample vaulted umbilicus and seems to me, though perhaps 

 related to Leptothyra, to be sufficiently distinct to be retained. If uot, the 

 name would replace Leptotliyra, having seventeen years priority, aud uot being, 

 so far as I can discover, otherwise ineligible. 



Leptothyra panamensis Dali,, n. sp. 



Plate 5, figure 9. 



Shell large for the genus, white, brilliantly pearly within, covered with an 

 opaque creamy white outer coat and a brilliantly polished translucent pcriostra- 

 cum ; apex eroded, followed by about three subsequent turbinate whorls; major 

 spiral sculpture of three strong distant keels, of which one appears on the spire; 

 close to the second the suture is laid, giving the elFcct of a very minute channel; 

 on the last whorl the second is at the periphery and more distant from the first 

 keel than from the third, which forms the margin of the base ; the relative dis- 

 tances of these keels may vary somewhat with the individual; beside the keels 

 the whole surface is covered with fine spiral threads with wider interspaces, there 

 are about a dozen between the first and second keels ; there is no axial sculpture 

 except lines of growth ; base rounded ; aperture round except where angulated 

 by the keels; body with a thin callus; pillar thickened, with a small obscure 

 tooth at the anterior end, where the adjoining lip is slightly patulous; outer lip 

 simple, throat pearly, smooth ; operculum lost. Height, 9.5 ; height of aperture, 

 5.5 ; max. diam. 11.0 mm. 



