C E R I T II I U M . 



Plate I. 



Genus CERITHIUM, Bruguiere. 



Testa marina, tiirrilu, irregnlurUer varicosu, loiiijitndhia- 

 litar plicatd sen tuboxidatd, anfractihus numerosis, 

 plerumque (jradatlm creseenlibiis ; aperturd suptrni in 

 canalem coidrucio, labia inlerno postice plus miiiiisce 

 calloso, caiiuli anlico plus miiiiisve prodiicto. 



Shell marine, turretcd, irregularly varicose, longitudinally 

 plaited or tubercnlated, whorls numerous, for the 

 most part graduaDy increasing; aperture above con- 

 tracted into a canal, inner lip posteriorly more or less 

 callous, anterior canal more or less produced. 



In the latest monograph of this genus of shells produced 

 by Mr. Sowerby, with assistance from Mr. Arthur Adams, a 

 large number of species are included which it may here be 

 convenient to separate. The genus Vertagus, characterized 

 by a reflected canaliferous tube, appears to form a natural, 

 and almost definable group. iUso, it may be advisable 

 to treat as separate genera those groups which contain the 

 shells of more fluviatile mollusca. Although the genus 

 Cerithopsis is excluded on account of the structure of the 

 animal, there does not appear to be any sufficient means 

 to distinguish the subcylindrical group of little species, 

 resembling the latter genus in form, to which some authors 

 apply the name "Billiiim," of which C. i-eticulatum is the 

 type. The half-a-dozen species which have been dis- 

 tinguished under the name " Coliiia," having the last whorl 

 ]nore or less contracted, are also included in the present 

 genus. 



The genus CeritJuum, as here constituted, contains 149 

 species, of which some few are described for the first time. 

 Their geographical distribution is very extended, the genus 

 being represented in North America as well as in South 

 Australia, in Europe, Asia, and Africa. On the whole, south- 

 ern climates seem most favourable to the development of 

 the race. The few species composing the " Colina" group 

 are from Port Natal. North America and Great Britain 

 present a few species, the latter very few, and those of the 

 " BiUiiim" group. But of the species whose localities are 

 known, no less than thirty-eight were collected by the late 

 Mr. Cuming in the Philippine Islands. 



Species 1. (Mus. Cuming.) 

 Ceritiiium citrinu.m. Cerilh. testa pyramidatu, solidd, 



spiraliter striata, citrind ; aiifraclibiis longitndinaVder 

 plicatis, medio ventricosis, superne planulatis, plicis 

 distantlbus, magnis, rotundia, ultimo anfractu uni- 

 varicoso, infra ntiindo ; aperturd magna, postice ca- 

 naliferd, anticii tuba canali/erd eloiKjatd, producld, re- 

 curvd, labro expaiiso, laqueato. 



The citron Cerithiu.m. Shell pyramidal, solid, spi- 

 rally striated, citron-coloured ; whorls longitudinally 

 plaited, ventricose in the middle, flattened above, 

 plaits distant, large, round, the last whorl with a 

 single varix, rounded beneath ; aperture large, with a 

 posterior canal, and an elongated, produced and re- 

 curved anterior canaliferous tube, outer lip expanded, 

 fluted. 



SowEBBY, Thes. Conch, vol. ii. p. 855. pi. 179. f. 66. 



Hab. Island of Masbate, Philippines. 



Distinguished from most other species by the elongated 

 and somewhat recurved canal. 



Species 3. (Fig. a, b, Mus. Cuming.) 



■Cekithium colu.mna. Ceritli. testa rugosd, brevittsculd, 

 veutricosd, varicibus irregularibus iiiagnis munitd, spi- 

 raliter crebri-liratd, loiigitudinaliter aiigulatim plicatd, 

 alba, inter plicasj'usco-nigrescente lineat'i ; anfraclibus 

 numerosis, medio angulatis, pUcis distantibus, acutis 

 armatis ; aperturd magna, postice canaliferd, antice 

 tubd canaliferd elongatd, subtortud, indidd, labro ex- 

 panso, laqueato. 



The column Cerithium. Shell rough, rather short, ven- 

 tricose, strengthened by large irregular varices, spirally 

 many-ridged, longitudinally angularly plaited, white, 

 between the plaits marked with bhickish-brown lines ; 

 whorls numerous, angular in the middle, ar.i ed with 

 distant, shaii^ plaits ; aperture large, with posterior 

 canal, in front provided with a long, rather tortuous 

 canal-tube, outer lip expanded, fluted. 



Sowerby, Genera of Shells, No. 43. f. 7. 



Ilab. Philippine Islands ; Cuming. 



Specimens of this species vary, some of them having 

 numerous irregular varices. The longitudinal plaits are 

 produced into angular points at the centre of the whoris. 



December, 1865. 



