122 CREITHIID.E — CERITHIUM. 



Section Triforis (sensu stricto). 



Shell longitudinally ribbed, with one or two spiral lines ; aperture 

 round, entire ; canal closed. 



T. PLICATA, Desh. Eocene, Paris basin. 



The genera Trituba, Stylia, Euthymia and Metalejns, Jousseaume, 

 1884, are synonyms. 



Section Ino; Hinds, 1844. 



Shell cylindrically subulate, elongated, with flattened whorls, 

 tuberculated in spiral series, spire sharp-pointed ; aperture entire, 

 margin continuous. 



T. CORRUC4ATA, Hinds. Inella, Bayle, 1879, was proposed 

 because Ino has been used twice in Entomology, but I see no occa- 

 sion for making the change for such reason at this late day. Ini- 

 foris, Jousseaume, 1884. is a synonym. 



Section Mastonia, Hinds, 1844. 



Shell swollen in the middle, contracted and rounded at the base, 

 tuberculated usually in two spiral series. T. vulpina, Hinds. 

 3Iastoniceforis, Jousseaume, 1884, and Monophorus, Grillo, 1877 

 {=Biforma, B. D. D.), are synonyms. 



Section Viriola, Jousseaume, 1884. 



Shell with strong smooth, spiral ridges and channels ; last whorl 

 flattened and angulated at the base. T. Bayani, Jouss. Jousseaume 

 makes C. dextroversa, Ads. and Reeve, the type of his group, but 

 that species is already the type of Seila, A. Ad., a section of 

 Cerithiopsis. The sculpture of the two groups is the same, but one is 

 dextral, the other sinistral ; I prefer to limit Viriola to the sinistral 

 shells. 

 Section Sychar, Hinds, 1844. 



Elongated, with rounded whorls. T. vitrea. Hinds. 



Genus CERITHIUM, Adanson, 1757. 

 Subgenus Cerithium (sensu stricto). 



€. NODULOSUM, Brug. PI, 19, figs. 13, 14 ; PI. 20, fig. 15. 



Ribs and tubercles crossed by spiral ridges and sulci, becoming 

 coarser on the base ; whitish or greyish, maculated and spotted with 

 chestnut and chocolate color. Length, 3-4 in. 



Singapore, Moluccas, Philippines. 



It is C. tuberosum, Dillw., and C. aluco, Born (not Linn.). 



