CERITHIUM.— Plate III. 



SowERBY, Ihes. Conch, sp. 29. 

 Hab. Guadaloupe, 



More irregular in form than the tme C. atratmn of 

 Born, the aperture more expanded, and the canal longer 

 and more defined. 



Species 17. (Mus. Cuming.) 



Cerithium polygonum. Ceritli. testa pyramidatu, al- 

 bida, griwscente, spiraliter profundi udcata, costh 

 magnis rotundis regularlbus sequeniibiis indutd, an- 

 fractibus numerosis, ultimo costd magna infra eincto, 

 aperturd intiis castaneo fascia (d, canal i brevitisculo, 

 labro sinuatu. 



The many-sided Cerithium. Shell pyramidal, whitish, 

 tending to grey, spirally deeply grooved, provided 

 with large regular ribs, following each, other (from 

 whorl to whorl), whorls numerous, the last girt with 

 a large rib beneath, aperture within banded with 

 chestnut, canal rather short, outer lip sinuated. 



SowERBY, Thes. Conch, sp. 23. 



Hnb. Port Essington ; Jukes. 



Ihis species was described by Jlr. Sowerby from the 

 incomplete but unique specimen in Mr. Cuming's collec- 

 tion. The large rounded ribs are continuous from whorl 

 to whorl, so as to give a many-sided form to the shell. 



Species 18. (Fig. a, b, Mus. Cuming.) 



Cerithium dialeucum. Cerilh. testa pyramidatd, rubra 

 vel griseo et albo alternatim fasciald, spiraliter casta td, 



longitudinaliter plicatd, plicis medio anfracliium aii- 

 gulntis, canali producta, subrecurvo. 



The half-white Cerithium. Shell pyramidal, banded 

 with red or grey and white alternately, spirally 

 grooved, longitudinally plicated, the plicae angulated 

 in the centre of the whorls, canal produced, slightly 

 recurved. 



Philippi, Abbildungen, pi. 1. f. 5. 



Hab. Island of Ticao, Philippines. 



This species presents some varieties of colour, but ail 

 preserving the general character of dark alternating with 

 I white stripes. 



Species 19. (Mus. Cuming.) 



Cerithium splendens. Ceritli. testa pyramidatd, medio 

 vix ventricosd, grised, varicibns albis, anfructibits mi- 

 merasis, castellis moniliformibiis, alternatim nigro- 

 punctaiis, spiraliter cinctd, aperturd ovatd, canali 

 brevi, labro subexpansa. 



The splendid Cerithium. Shell pyramidal, very 

 slightly ventricose in the middle, grey, varices white, 

 whorls numerous, spirally girt with little beaded ribs, 

 in which the beads are alternately black aiul white, 

 aperture ovate, canal short, outer lip expanded. 



Sowerby, Thes. Conch. Cerithium sp. 101. 



Hub. Island of Zebu, Philippines ; Cuming. 



This shell is much more pyramidal and tapering than 

 moniliferum, which it resembles in other respects. On 

 most of the costellae the bead-like tubercles are alternately 

 black. 



