444 GASTROPODA. [Pectinibranchin . 



Fam. VOLUTID^], Gray. 



Animal having a broad foot, the head very flattened, and trans- 

 versely widened, with the eyes on the sides, the tentacles distant ; 

 siphon with internal appendages. Formula of radula usually 0+1+0, 

 exceptionally 1 + 1 + 1. 



Shell usually large, elongated, more or less oval ; spire relatively 

 short ; protoconch smooth, very variable, sometimes small and 

 conoidal, or large and bulbose, with the nucleus very little elevated, 

 but occasionally distinctly mucronate ; aperture elongated, some- 

 times widened, truncated and often deeply excavated below ; outer 

 lip generally thick, more or less straight ; columella callous, obliquely 

 twisted below, and ending in a point usually lower than the extremity 

 of the opposite lip ; the plaits extremely variable, mostly numbering 

 3 to 5, very oblique, thin and unequal, or thick, subtransverse, and 

 nearly equal ; inner lip more or less thick, usually spreading over 

 the base. An operculum is but rarely present. 



The majority of the members of this family belong to the Southern 

 Hemisphere ; most of them live in the littoral and laminarian zones, 

 but specimens have been obtained in much greater depths (1.600 

 fathoms). 



Fossil. The Volutidce first appear in the Cretaceous. 



Genus 1. FULGURARIA, Schumacher, 1817. 



Fulguraria, Schumacher, Essai Nouv. Syst., 1817, 242. Type : Valuta ru- 

 pestris, Gmelin. 



Shell large, usually narrowly elongate ; protoconch bulbose, often 

 very large, the nucleus rolled up laterally and rounded ; aperture 

 more or less widened, lightly notched at the base ; outer lip not re- 

 flexed ; columellar plaits variable in number, moderately oblique. 



Subgen. 1. ALCITHOE, H. and A. Adams, 1858. 



Alcithoe, H. & A. Ad., Ad. G.R.M., i, 164 ; ii, 617. Type : Valuta pacifica, 

 Solander (= arabica, Marty n). 



Shell large, ovately fusiform ; spire produced, conic ; protoconch 

 bulbose, larger than the succeeding whorl, sometimes costulate : the 

 body-whorl large, somewhat swollen at the middle, attenuated and 

 excavated at the base ; fasciole not elevated ; aperture oval-elongated, 

 with a canaliculate channel above, but little narrowed below, broadly 

 truncated and excavated ; outer lip dilated, subreflexed, nearly 

 vertical, smooth inside, retrocurrent towards the suture ; columella 

 almost straight, with 3 to 7 equidistant, thick, and oblique plaits, 

 lightly recurved below, and ending in a pointed beak ; inner lip thin, 

 spreading broadly over the body-whorl. No operculum. 



