LEPTOTHYRA. 247 



and by Woodward. (PI. 00, figs. 61, 62.) I do not understand 

 the discrepancy between the description of the operculum and De- 

 shayes' figure of it. The main character distinguishing Gollonia 

 from Leptothyra seems to be the peculiar peristome of the former. 

 Fischer says of it: "peristome continu, epaissi, dilate, excepte sur le 

 bord columellaire ; labre epais, parfois su])double on subreflechi. '■' 



^ ^ >!< 



Les coquilles de ce groupe ne paraissent pas avoir ete nacrees- 

 Leur opercule ressemble a celui des Leptothyra, mais leur ouvertiire 

 rappelle celle des Liotia." (Manuel de Conch., p. 812.) 



There are numerous Tertiary species. 



Note. The operculum of Leptothyra frequently otlers excellent 

 specific characters, just as it does in Turbo and AstraUum ; and at- 

 tention to these will often enable one to readily separate sj^ecies of 

 which the shells exhibit considerable similarity. 



L. CARPENTER! Pilsbry, 1888. PI. 39a, figs. 26-29. 



Shell small, globose, very solid, imperforate, spire conic, more or 

 less depressed ; suture moderately impressed ; whorls 5, slightly 

 convex, the last decidedly deflected toward the aperture, encircled 

 by about fifteen subequal spiral lira?, separated by interstices about 

 as wide as the ridges ; incremental strire generally strongly devel: 

 oped, causing the lirse to appear nodose or somewhat irregular, and 

 the interstices to appear pitted ; aperture oblique, pearly white 

 within, about half the length of shell ; columella arcuate, base ob" 

 soletely uni- bi- or tri-dentate ; color red, ashen or purple. 



Alt. 8, diam. 8-9 milh ; dark form alt. 5, diam. 5 mill. 



Cape St. Lucas, L. California to Vancouver Id. 



Operculum (pi. 60, fig. ^'o) rounded oval; outside much thinner 

 and less elevated around the margins than that of X. sanguinea, 

 slightly concave in the middle, nearly smooth. 



This is L. cocci neus of Troschel, not Miihlf., Ij. calijornicus von 

 Martens, not of Philippi, L. sanguineus of Carpenter and authors 

 generally, not of Linn., and vav. purjmreus Carpenter, (preoc). 



The Californian shells a})pear to me to be quite distinct from the 

 Mediterranean species ; I have been unable to find, in the numerous 

 specimens of the latter form which I have examined, any trace of 

 the peculiar indentations in the grooves or of the uneven character of 

 the lirae which are so conspicuous in the Californian species. The 

 lirse ofX. Carpenteri ai-e genei-ally smaller and more numerous; 

 about five or six are visible on the penultimate whorl ; and those 



