8TOMATELLA. 7 



folds below the suture ; aperture either oblong or transversely oval, 

 and longer than wide or the reverse ; pearly inside. No operculum. 

 Type, S. phymotis Helbling. 



East Indies. 



Subgenus Microtis H. & A. Adams, 1850. 



Shell spiral, suborbicular, depressed, with two tuberculated ridges ; 



spire slightly projecting ; aperture very large, wider than long, 



pearly within ; columellar margin spiral, visible as far as the apex 



of the spire. Operculum none. (Ad.) Type, M. tuberculoid Ad. 



Philippines; Neiv Caledonia; Paumotus. 



Genus GEN A Gray, 1850. 



Shell subspiral, Haliotis-shaped, oblong ; spire minute, sub-lateral 

 surface smooth or striated ; aperture very large, nearly as long as 

 the shell, pearly within. Operculum none. Type, G. planidata 

 Lam. 



Indian Ocean to Central Pacific. 



Subgenus Plocamotis Fischer, 1885. 



Shell polished, the body-whorl not striated as it is in typical Gena, 

 and the animal with epipodial cirri. Type, G. Icevis Pease. 



Genus BRODERIPIA Gray, 1847. 



Shell oval, limpet-shaped, bilaterally symmetrical when adult, the 

 apex either subcentral or posterior, and either remaining as a minute 

 recumbent spiral or lost in the adult shell. Interior brilliantly 

 iridescent or almost deprived of nacre. Type, B. rosea Brod. 



S. Pacific and Indian Oceans. 



Genus STOMATELLA Lamarck, 1819. 



StomatellaJuA'M. (Philos. Zool., 1809, mentioned but not described, 

 and no species cited) Anim. s. Vert. vol. vi, p. 209, 1819. First 

 species, S. imbricata Lam. 



The smaller foot, provided with an operculum separates this genus 

 from Stomatia and Gena. Several species referred to Euchelus have 

 a great likeness to the shells of this genus, partaking of the form 

 and sculpture to a remarkable extent. E. cancellatus Krauss is an 

 example of this. That species is however umbilicated, and seems to 

 belong rather to the Trochidce than to Stomatella. An examination 



