478 GASTROPODA. [Pectinibranchia. 



5. Drillia optabilis, Murdoch and Suter, 1906. Plate 21, fig. 7. 



Drillia optabilis, M. & S., T.N.Z.I., xxxviii, 1905 (1906), 283, ])1. 21, f. 9. 



Shell small, narrow, turriculate. last whorl shorter than the spire, 

 clathrate, aperture pyriform. canal short. Sculpture : On the spire- 

 whorls 3 spiral equidistant cords, which are crossed by axial also 

 equidistant threads, forming small beads at the intersections, and 

 squarish interstitial depressions ; there are about 21 beads on a row ; 

 on approaching the base the spirals are getting narrower than the 

 interspaces and the beading less prominent ; upon the beak there 

 are small irregular threads crossed obliquely by the plications of 

 the fasciole. Colour greyish-white. Spirt' turriculate, not very con- 

 spicuously shouldered, the height nearly twice that of the aperture. 

 Protoconch with a globular and obliquely tilted nucleus. Whorls 7, 

 narrowly angled and excavated above, sides almost straight ; base 

 convex and narrowed to a short and anteriorly sinuated beak. Suture 

 bimarginate, above by a minute threadlet, below by a broad and 

 heavy cord which is obliquely irregularly plicated. Aperture pyriform, 

 angled above, with a concave inner wall, ending in a short broad 

 canal, which turns slightly to the left. Outer lip curved, imperfect ; 

 the lines of growth would indicate that the sinus is situate in the 

 excavations below the sutural cord, that it is small and moderately 

 deep. ColtaiK'lld at first straight and then slightly twisted to the 

 left, ending in a sharp point. Inner lip rather broad on the columella, 

 spread as a thin layer over the parietal wall. Operculum unknown. 



Diameter. 3-9 mm. ; height. 10-7 mm. Angle of spire. 22. 



Animal unknown. 



Type in the Dominion Museum, Wellington. 



Hob. Off Great Barrier Island, in 110 fathoms. 



6. Drillia Trailli, Hutton, 1873. Plate 46, fig. 24. 



Pleurotoma Trailli, Hutton, C.M.M., 11 ; M.N.Z.M., 42. Drillia Trailli, 

 Hutt., Man. Conch (1), vi, 206, pi. 34, f. 90; pi. 12, f. 37. Surcula 

 Trailli, Hutt. : Suter, T.N.Z.I., xxxi, 90; xxxiv, 211: Index, 71: 

 P. Mai. S., vi, 201. Drillia oemula, Angas, P.Z.S., 1877, 36, pi. 5, f. 9 ; 

 M.N.Z.M., 44. D. bcetica, Reeve : Hutton, J. de Conch., xxvi, 16 ; 

 not of Reeve. Drillia (?) maorum, E. A. Smith : Hutton, P.L.S. N.S.W., 

 x, 116 ; not of E. A. Smith. 



Shell fusiform, turriculate, fairly solid, axially costate and the 

 suture strongly marginate, brown. Sculpture consisting of slightly 

 oblique, distant, broadly rounded axial costre, about 15 on a whorl 

 not extending over the base on the last whorl ; below the suture there 

 is a distinct spiral ridge, margining it, the space to the angle of the 

 whorls is smooth, save crescent-shaped growth-lines ; from the angle 

 to the suture below the axial ribs are crossed by a number of spiral 

 ridges, rendering them, somewhat nodulous ; the whole of the base is 

 spirally ridged, the ridges closer and finer upon the neck of the canal. 



