338 



Mitra retrocurvata, n. sp. PL xxiv., ligs. 4 and 5. 



Shell fusiform, of 8 whorls, including a prominent j^ro- 

 toconch of 2 smooth, well-rounded whorls, with a blunt apex. 

 Spire-whorls convex, with deeply-impvessed sutures. Body- 

 •whorl large, roundly contracted at the base into a snout, well 

 curved dorsally and to the left. Aperture oblong-elliptical, 

 opening gradually into an open canal with a wide, shallow 

 notch. Outer lip thin and simple. Inner lip a complete 

 very thin applied glaze. Columella very long and convexly 

 curved, with four oblique plaits, the highest rather distant. 

 Valid axial ribs, from suture to suture, twenty-one in the 

 body-whorl, concave forwards, trigonal, with widely-sloping 

 sides, vanishing rapidly below the periphery of the body- 

 whorl. Under the microscope a few obsolete narrow spirals 

 are detectible. Over the base are sixteen oblique spirals, issu- 

 ing from beneath the inner lip, most valid in front and grad- 

 ually vanishing upwards ; among them are the larger colum- 

 ella plaits. The accremental striae are fine, most marked on 

 the back of the canal, where they validly cross the oblique 

 spirals. Colour yellow-brown, with a white central broad 

 band divided by a narrow colour band ; the ba&e is indis- 

 tinctly axially flamed with white. 



Dim. — Length, 16'5 mm. : body-whorl, 1075 mm. ; width, 

 625 mm. 



Locality. — Type from 110 fathoms off Beachport, with 

 7 others ; in 150 fathoms, 4 moderate. 



The special character is the arched canal. In some of 

 the cotypes the axial ribs fade out on the third whorl, and 

 in others on the fourth. 



Olivella (?) adiorygma, n. sp. PI. xxv., figs. 3 and 4. 



Shell small, solid, obliquely elongate-oval, smooth and 

 white : apex blunt ; whorls four, sloping convex. Suture 

 linear, not canaliculate. Aperture oval, narrowed behind, 

 widely open in front, notched ; outer lip ascending at the 

 suture, simple, bevelled inside ; inner lip a glaze over the 

 columella, which has no plaits. 



Dim. — Length, 52 mm.; of body-whorl, 3'35 mm.; 

 width, 2'3 mm. 



Locality. — Type from Backstairs Passage, 17 fathoms, 

 with 1 other specimen ; Gulf St. Vincent, depth unrecorded, 

 2, all dead. 



Diagnosis. — It differs from Olivella in the absence of a 

 canaliculate suture, and from the Volutidae in its smooth col- 

 umella. Its generic location is not known to me. 



