364 _ EEV. E. BOOG WATSON ON THE 



rated outer and inner edge. H. O'S. B. 0'45. Penultimate 

 whorl, 0-18. Mouth, height 0-33, breadth 0-24. 



Mr. Marrat, of Liverpool, whose labours on the genus Nassa in 

 particular are well known, and who has had the goodness carefully 

 to examine the whole of the ' Challenger ' species of the group, 

 considers this species to be his N. Icevigata {■= glabella, Marr. nee 

 Sow.), an opinion which I am not able to accept. With a con- 

 siderable general resemblance, the form of the shell is very dif- 

 ferent. In N. Icevigata the shortness and breadth of the last 

 whorl gives a contour-line totally unlike that of ISf. levuhensis, 

 which is narrow at the periphery and comparatively long in the 

 base. It has points of resemblance to N. 7Jto7iile, Kien., to iV. 

 algida, Eeeve, to N. coronata, Lam., and to N. cremdata, Brug., 

 but is certainly distinct from them all. It most of all resembles 

 one of the depauperated forms of J^. canaliculata, Lam., in some 

 of which the canaliculation of the suture becomes very obsolete ; 

 but in none of these is there so sharp a flange round the anterior 

 canal, none have so deep a furrow at the origin of the pillar, nor 

 so sharp a thread in front of that furrow, and in all the apex has a 

 broader base, and is higher, sharper, more conical. The operculum, 

 too, is quite unlike, being in these very much smaller, more oval, 

 and without serrated edges. 



2. Nassa psila, n. sp. (ipiXbs, rubbed.) 



St. 185 B. August 31, 1874. Lat. 11° 38' 15" S., long. 143° 

 59' 38" W. Ofi" Eaine Island, Torres Straits. 155 fms. Sand 

 and shells. 



Shell. — Very thin, glassy, polished, white, with some brown 

 stains ; conical, scarcely oblique, with a high scalar spire, a small 

 blunt apex, a short truncate base, a sharply flanged canal, and 

 a very small snout. Sculpture. Longitudinals — the earlier whorls 

 are crossed by numerous regular flue riblets parted by very similar 

 furrows ; they are straight, but incline a little obliquely to the left ; 

 they hardly increase in size, but on the last 1| whorls become obso- 

 lete ; the lines of growth are very fine. Spirals — below the suture 

 is a narrow horizontal shelf, whose sharp edge is ornamented with 

 an expressed row of blunt tubercles ; these are formed by a deepish 

 furrow isolating the tops of the ribs ; narrow shallow furrows 

 stipple the interstices of the riblets ; these become faint on the 

 last whorl, but increase in strength and become more continuous 

 as they approach the outer lip ; they also increase in strength 

 towards the point of the base. Colour horny or translucent 



