REPORT ON THE GASTEROPODA 559 



of its point. Inner lip straight and thin. H. 0'107 in. B. 0"044. Mouth, height 0*024, 

 breadth 0"022. 



Thislittle shell is very probably not full-grown, bat is marked by very distinct features . 



23. Bittium porcellanum, 1 n. sp. (PI. XXXVIII. fig. 8). 



Station 185b. August 31, 1874. Lat. 11° 38' 15" S., long. 143° 59' 38" E. Eaine 

 Island, Cape York, North-east Australia. 155 fathoms. Coral sand. 



Shell. — Small, narrow, conical, subscalar, porcellanous, glossy, brown-topped, white- 

 tipped, longitudinally ribbed, barely tubercled or spiralled, with square whorls, a con- 

 stricted suture, and a short flat base. Sculpture: Longitudinals — there are in the middle 

 of each whorl about 15 ribs, which extend to the suture but not to the base ; near the 

 top and bottom each of these swells into a small blunt round tubercle, which is very 

 little prominent ; there is no connection between these tubercles from rib to rib ; there are 

 obsolete microscopic longitudinal scorings, which are the lines of growth. Spirals — the 

 surface is very faintly marked with microscopic lines ; the constriction at the top and 

 bottom of each whorl forms a strong sutural furrow, the upper and under side of which is 

 angulated by the slight projection of the rib tubercles ; at the periphery round the outside 

 of the base runs a fine thread, the upper edge of which can be seen in the sutural furrow ; 

 close within this thread lies another much like the first ; close round the top of the pillar 

 coil other two slightly feebler ; the flat centre of the base is only scored by radiating lines. 

 Colour porcellanous white and glossy, the apex is dull and yellowish chestnut, with a 

 whitish tip. Spire high and narrow, conical. Apex consists of 4 conical whorls, of which 

 the latter 2\ are chestnut coloured, are scored in the middle with two fine threads, and 

 have on the shoulder below the shallow suture fine microscopic longitudinal puckerings ; 

 the first whorl and a half are dull whitish, and form a very small rounded top, on which 

 the minute tip just rises into view. Whorls 8, besides those of the apex, short and narrow, 

 angular, constricted above and below ; the last begins to enlarge ; it is angulated round the 

 edge of the flat base. Suture in itself very feeble, but strongly defined by the contraction 

 at top and bottom of each whorl. Mouth lozenge-shaped, having straight sides and four 

 distinct angles. Outer lip straight and leaning to the right, angulated at the perii3hery, 

 and then straight and slightly advancing on the base. Pillar long, straight, leaning a 

 little to the left, with a thin expanded edge ; in front it is narrowed off to a very fine point, 

 in advance of which is the shallow open oblique canal. H. - 15 in. B. - 06. Mouth, 

 height 0-04, breadth 0*03. 



This is a very aberrant form of Bittium, both in colour and in sculpture, but the form of the 

 mouth unmistakably connects it with this genus. 



1 So called from its texture and colour. 



