833 



not fleshy and tubercular, or produced posteriorly ; lateral mem- 

 brane very wide, the circumference regularly fimbriated. 



Operculum orbicular, thin, horny, multispiral. 



Shell spiral, suborbicular, depressed, transversely ribbed or sul- 

 ciferous ; spire more or less elevated, whorls rounded ; aperture 

 large, wider than long, pearly within. 



Some of the species approach very nearly in character the genus 

 Euchelus of Philippi, in the sub-family Trochina. Until the animals 

 of all the species are known, they must of necessity be grouped 

 artificially by a consideration of their shells, which, as a general 

 rule, are transversely ribbed or grooved. The presence of an 

 operculum is also a useful guide in distinguishing the genera, 

 being already known in -6', cancellata, S. mlcifera, and S. macu- 

 lafa. The species of Euchelus may be known from the shells of 

 Stomatella in the outer lip being double at the margin, and in 

 the inner lip being furnished with a tooth. 



[The Author, having examined, in company with the Editor, all 

 the species, with a view to separate, by some definite rule, the 

 Stomatella from the Stomatia, could find no character in the 

 shell so suitable for that purpose as the wrinkling of the last 

 whorl at the suture in Stomatice. All the Stomatella, known as 

 such by the presence of an operculum or a retractile animal, are 

 without the wrinkling, while the species known as Stomatia have 

 it. We have therefore adopted this as a (perhaps artificial) sign 

 in arranging with either genus the species whose animals are 

 unknown.] 



1. Stomatella imbricata (pi. clxxiv. f. 1), Lamarck, Encycl. 

 pi. 450, t^ ab; Hist. ed. Desh. vol. iv. p. 16. 



S. testa suborbiculari, convexo-depressa, scabriuscula, grisea; 

 sulcis transversis, confertis, imbricato-squamosis ; spira subpromi- 

 nula. 



Shell suborbicular, convexo-depressed, rugose, griseous, with 

 transverse, imbricato-squamous, close-set grooves; spire rather 

 prominent. 



Torres Straits. Jukes. (Mus. Cuming.) 



2. Stomatella sulcifera (pi. clxxiv. f. 3), Lamarck, Hist, 

 ed. Desh. vol. ix. p. 16. 



S. testa, suborbiculata, convexa, tenui, transversim sulcata, lon- 

 gitudinaliter tenuissime striata, griseo-rubente, sulcis scabrius- 

 culis ; spira prominula. 



Shell suborbiculate, convex, thin, transversely sulcate. longitu- 



