M I T R E L A monodonta, 

 The Vol ate Mitres. 



Family Volutidee. Sub-family Mitranse. Genus Mitreola. Sw. 

 Generic Character. 



Shell fusiform, smooth ; the middle plaits of the pillar largest 

 apex of the spire generally papillary. 



Specific Character. 



Shell ovate, acute, smooth ; spire slightly striated, the tip papillary; 



outer lip within, gibbous. 

 Mitra monodonta. Lam. Syst. 7, p. 324. 



We feel much obliged to Mr. G. B. Sowerby for calling our 

 attention to the remarkable construction of this Volute 

 Mitre, of which we had not then seen a specimen. We view 

 it as supplying* that link of connection between the Volutinse 

 and the Mitranse, the Volute and the Mitre shells, which 

 we had long been in search of. Of the genus, however, we 

 know as yet but of two species, represented on the plate 

 somewhat larger than their natural size. We have also 

 added a figure of our Mitra acuminata, to shew how 

 beautifully Mitreola is represented by the fourth type of the 

 genus Mitra, as now restricted, to which type (represented 

 by M. Zebra), acuminata also belongs : both, as prototypes 

 of the Strombidee, have the outer lip gibbous near the top ; 

 but the plaits of the pillar are totally different, while the 

 spire of one is acute, and of the other papillary. M. mono- 

 donta is a Grignon fossil : some specimens are so well 

 preserved, that the colours may be traced in the appearance 

 of zebra-like stripes : thus strongly corroborating our views 

 on its true analogies. 



MITRA terebellum. 



Shell fusiform, turrited, smooth, base striated ; channel sub-entire, 



Mitra terebellum. Lam. Sys. 7, 325. Envy. Meth. pi. 392, a, b, c,d? 



Of this Grignon fossil, we have but one specimen: it 

 agrees with Lamarck's description, but not with the figure 

 be quotes; and it may possibly be a distinct species between 

 his M. plicatella and terebellum. The plaits are like those 

 of M. monodonta; but the tip of the spire is acute, and 

 slightly plaited. 



l'<>8. 



