THE MOLLUSCA HEDLEY. 431 



CERITHIUM MACULOSUM, Mighels. 

 Kobelt, Conch. Cab., "Cerithium," 1895, p. 499, pi. xxxv., figs. 



18, 19. 

 One dead shell from the lagoon beach. Also occurs at Hawaii. 



CERITHIUM ROSTRATUM, Sowerby. 

 Tryon, op. cit, p. 130, pi. xxiii., figs. -90, 91. 



Three specimens from the lagoon beach. There are examples 

 in this Museum from the New Hebrides ; Pease observed it in 

 Hawaii ; Hugh Cuming at Marutea, Paumotus ; Brazier at San 

 Christoval, Solomons; the "Chevert" took it in Torres Straits, and 

 Tryon gives it from Fiji. 



CERITHIUM OCEANICUM, sp. nov. 

 (Fig. 19). 



Shell rather elongate, almost truncate anteriorly. Colour 

 uniform chocolate. Whorls eight, the upper biangulate, the last 

 equal in length to the remainder. Sculpture : there are on the 

 penultimate whorl (including varices) twenty low, rounded, longi- 

 tudinal ribs, which crenulate the suture. These cross regularly 

 from whorl to whorl, becoming fewer but proportionately stronger 

 as they ascend the spire ; on the last whorl they 

 become evanescent. Two spiral lines of granules 

 descend the spire, appearing on the crest of each 

 rib as a smooth boss. On the body whorl there 

 are besides, beneath these, three spiral lines in 

 which the beads have nearly fused into a smooth 

 continuous ridge, the uppermost of these is some- 

 times apparent in the spire as a super sutural 

 fascicle. The whole surface of the shell except 

 the beads, is covered by close, microscopic, raised 

 spiral hair lines. Three, obliquely ascending, con- 

 tinuous lines of varices mount the spire a third of 

 a whorl apart. Aperture slightly oblique, semi- 

 lunate ; anterior canal hardly more than a notch, 

 directed sideways; columella anteriorly truncated, 

 externally wrinkled and curved downwards and outwards, inter- 

 nally with a low ridge-tubercle, callus on body whorl medium ; 

 outer lip strongly variced behind, edge sharp, notched by the 

 major spiral sculpture, finely grooved within. Length 8, breadth 

 4 mm. 



A single, perhaps not quite adult specimen from the lagoon beach. 



This shell seems to be a dwarf of the species which Sowerby 

 has figured* as "Cerithium granosus, Kiener." The shell which 

 Kiener himself figures! so differs in contour, sculpture, size, 



* Sowerby Thesaurus Conch, ii., 1855, pi. clxxxi., fig. 123, 124. 



t Kiener Coquilles Vivantes, Canaliferes i. (n.d.), pi. iv., fig. 5, p. 57. 



