540 GASTROPODA. [Opisthobra nchia. 



loosely coiled whorls, which are entirely open from below ; spire 

 sunken ; aperture very large, broadly effuse below ; the outer lip 

 retracted, joining a wide sinus above ; columella thin, arcuate. 



The egg-capsules are gelatinous, hydrophanous, ovate, containing 

 very numerous eggs arranged in single file, on a very long funiculus, 

 folded in a loose spiral. The embryo has a spiral shell, an operculum. 

 and is capable of swimming by means of a ciliated veil. 



The animals composing this genus are blind, like most creatures 

 that seek their food by burrowing. They frequent mud-flats, which 

 they perforate near the surface, and probe with their flattened heads 

 for the small bivalves which constitute their prey ; these they seize 

 and swallow entire, breaking their shells by means of their testaceous, 

 muscular gizzards. 



Distribution. All seas, from low-water mark to a depth of about 

 1,000 fathoms. 



Fossil in the Cretaceous and Tertiary. 



KEY TO SPECIES. 



A. Shell irnperforate, with distinct close spiral grooves . . . . constricta. 



B. Shell umbilicate, with inconspicuous distant spiral striae . . umbilicata. 



1. Philine constricta, Murdoch and Suter, 1906. Plate 23, 

 fig. 7. 



Philine constricta, M. & S., T.N.Z.I., xxxviii, 1905 (1906), 278, pi. 21, f. 1. 



Shell small, thin, convolute, imperforate, spirally grooved, auriform, 

 slightly contracted above. Sculpture consisting of shallow fine linear 

 spiral grooves, leaving broader bands between them, crossed by ir- 

 regularly arranged' incremental hues. < '/ilnnr white. Spire concave. 

 Protoconch minute, smooth. Whorls li, very rapidly increasing, the 

 last very large, contracted below the vertex. Aperture elongately oval, 

 acuminate above. Outer lip sharp, lowly convex, microscopically 

 transversely striated inside. Lower Up regularly rounded. Inner lip 

 forming a broadly spread callosity upon the body, narrow on the 

 concave oblique and twisted columella. 



Diameter. 3 mm. ; height. 5 mm. 



Animal unknown. 



Type in the Dominion Museum. Wellington. 



Hab. Off Great Barrier Island, in 110 fathoms. 



Subsp. auriformis, Suter, 1909. Plate 23, figs. 8, a-d. 



Philine constricta auriformis, Sut., P. Mai. S., viii, 1909, 257, pi. 11, f. 1417- 

 P. Angasi, Crosse : Hutton, J. de Conch., 1878, 41 ; C.M.M., 53 ; 

 M.N.Z.M., 123 ; not of Crosse. P. aperta, L., Index, 69 ; not of Linne. 



Shell auriform, subquadrangular, thin and fragile, finely spirally 

 striated, white. Sculpture the same as in the species. Colour white, 

 iridescent in some parts. Epidermis very thin, transparent, shining. 

 Spire sunken, the outer lip narrowly reflexed over the centre. Body- 



