494 THE VOYAGE OF H.M.S. CHALLENGER. 



This species faintly resembles some of the large forms of Odostomia interstincta, Mont., but is 

 larger, more cylindrical, with a higher, rounder, not flattened tip, an unimpressed suture, and a 

 different sculpture. The solitary specimen is somewhat rubbed, and has a broken lip, facts which 

 prevent minuter description of certain features than that given above. 



25. Odostomia (Turbonilla) dipsyclia, 1 n. sp. (PI. XXXII. fig. 8). 



Station 188. September 10, 1874. Lat. 9° 59' S., long. 139° 42' E. West of Cape 

 York, North-east Australia. 28 fathoms. Green mud. 



Shell. — Strongish, subcylindrical, very blunt, ribbed, and spirally striate, with a very 

 notable, half-turned-over, elongate, projecting, Clausilia-like sinistral apex, slightly im- 

 pressed suture, short rounded base, and small, oval, but angulated mouth. Sculpture : 

 Longitudinals — there are on each whorl about 16 rather high, narrow, slightly flexuous 

 distant ribs, of which one here and there tends to become varicose ; they are parted by 

 square furrows of more than double their breadth ; they cease abruptly at the edge of the 

 base where the surface is levelled up, and only bears faint traces of the ribs. Spirals — 

 the furrows between the ribs are scored with about 7 flat rounded unequal threads, of 

 which the fifth and sixth (reckoning from above) lying in the middle of the whorl tend to 

 become stronger than the rest ; on the base these, like the ribs, are only faintly visible. 

 Colour ivory white. Spire subcylindrical, tapering but slightly, and ending at the top 

 very abruptly. Apex consists of 3^ whorls of rapid increase, forming a little Clausilia-like 

 shell, lying quite on its side, not at all immersed, and projecting prominently beyond the 

 line of the spire. Whorls (exclusive of those of the embryo) 7, short, slightly tumid below, 

 flatly conical above, and very shortly and faintly contracted at the suture : the last is short 

 and small, with a flatly rounded base. Suture a little impressed and submarginated on 

 the upper side by the edge of the basal thread. Mouth small, oval but pointed above, 

 and angulated at the top and point of the pillar. Outer lip slightly curved, subangulated 

 at the lower outer corner, rounded on the base. Inner lip very slight on the body, angu- 

 lately concave at the base of the slightly oblique and subtwisted pillar, which a fuller 

 depression encompasses. H. 0"11 in. B. 0'03. Mouth, height 0*02, breadth 0*017. 



Var. incerta, Watson. 



September 8, 1874. Flinders Passage, Cape York. 7 fathoms. 



A smaller, narrower, more conical, and pointed form, with convex whorls, a more 

 distinctly marginated suture, more direct but oblique ribs, and almost obsolete spiral 

 threads. 



1 &i-^uxo{, double-minded, with reference to the great contrast between the apex and the rest of the shell. 



