36 lANTHINA. 



Genus lANTHINA, Lam., 1799. 

 I. FRAGiLis, Lam. PI. 9, figs. 94-5 ; PI. 10, figs. 6-10. 



Whorls slopingly convex, with obtusely angulated pci-iphen^, 



outer lip of aperture very slightl}^ sinuous, violaceous white 



above, uniform purplish or violaceous below. Diam. 15 inches. 



Mediterranean, Atlantic 0., Indian 0., Pacific 0. 



This is probably Linuteus' Helix lanthina. 



Keeve and others distinguish two species which they suppose 

 Lamarck at first confounded under the uame of I.f)-agilis ; they 

 restrict this name to the more acutely angulated forms (figs. 94, 

 3, etc.), whilst /. communis, Lam. (fig. 99) — the name by which 

 he intended to replace his I. fragilis — is reserved for those with 

 obtuse pei'iphery. I confess that I cannot divide tliem satisfac- 

 torily ; consequently I include liere as synonyms a series of 

 intermediates, which have received the names of: 



/. Costee, Morch, proposed for /. bicolor, Costa (not Menke) ; 

 I. vulgaris. Gray ; Helix lamthina, Forslial ; J. violacea, Adams ; 

 /. penicephala, Peron ; I. violacea, Morch ; J. grandia, Brown ; 

 I. striulata, Carp. =: I. Carpenteri, Morch (fig. 3), and var. con- 

 torta. Carp., from Mazatlan ; I. Orhignyi, Morch ; /. hicolor, 

 Menke. 



Var. PLANOSPiRATA, Ads. and Reeve. Figs. 94-98. 



Depressed, with slopingly convex whorls, obliquely plicately 

 striated ; columella arched, somewhat diiately reflected ; aper- 

 ture transverse, a little sinuous on the middle of the outer lip. 



Diam. 1'4 inch. 



Atlantic Ocean, St. Helena, etc. 



Maybe nominally distinguished from I. frag His by its more 

 rounded periphery and more depressed spire, as well as by the 

 light color of the base immediately arouud the columella; but 

 apparently connects with it by intermediate stages. Among 

 these, having the form of planospirata, but with usually uniform 

 purple base, may be placed here as synonyms /. depressa, 

 Reeve (fig. 97); /. cierulata, Reeve (fig. 9f5) ; /. casta. Reeve 

 (fig. 95) ; I. balteata, Reeve (fig. 98) ; forms witli more elevated 

 spire, approaching I. fragilis are I. bicolor and I. fragilis, of 

 Lesson. 



