MOLLTJSCA OF THE ' CHALLEISTGEE, ' EXPEDITIOlSr. 321 



rises and is angulafced at tlie outer upper corner of the shell : 

 from this point its edge advances and its line is slightly convex, 

 tending in front to become straight ; at the lower outer corner 

 it is angulated, and across the base is abruptly truncate. Inner 

 lip has a very thin glaze; it is flatly convex on the body, straight 

 and elongately oblique on the pillar, which presents no tooth 

 but has a thin, defined, hardly twisted edge, and is abruptly cut 

 off" in front, being there a strong prominent point. L. 0"083. 

 B. 0-044. Mouth at same place, B. 0-007. 

 This is very possibly a young shell. 



3. Ctlichna ceisptjla, n. sp. 



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

 59' 38" E. Eain Island, Cape York, N. Australia. 155 fms. 

 Sand, shells. 



SlieU. — Narrowly oblong, more contracted above than below, 

 with the greatest breadth below the middle, obliquely truncate above 

 and below, thin, translucent, glossy, very faintly spirally striate 

 all over ; the top is like that of a Volvula, but beside the promi- 

 nent lip the axis is perforated: there is a strong pillar-tooth. 

 Sculpture. Longitudinals — the lines of growth are very slight 

 and unequal. Spirals — the whole surface is covered with very 

 slight, superficial, fretted, rather unequal, and somewhat remote 

 furrows. Colour translucent glossy milk-white. Mouth long 

 and narrow above, rising and retreating at the top of the shell, 

 widening in front, but not very large even there. Outer lip rises 

 from the edge of the axial pore, and forms the top of the shell ; 

 at this point it is narrowly rounded and retreats very much, 

 below this its edge advances and its direction is obliquely forward 

 to the right ; in front it retreats rather rapidly and sweeps freely 

 round the base to the point of the pillar; it is a little bent in 

 about the middle, but is very patulous on the base. Top is very 

 small, and fully half of it is covered by the lip, but behind this 

 there is a minute conical depression with a defined rounded edge. 

 Inner lip is regularly arched on the body, where there is a thin 

 glaze, which becomes thick on the pillar with a twisted sharply- 

 defined edge. Pillar bears a strong, almost direct, tooth, with a 

 well-marked broad furrow between it and the lip-edge. H. 0"16. 

 B. 0.-075. B. of mouth at same place, 0*017. 



This species is deceptively like a Volvula. It resembles Bulla 

 parallela, Grould, but is smaller, is more contracted above, and is 



