CERITHIDEA. 



Plate I. 



Genus CERITHIDEA, Swuimon. 



Te-i/a pyramidalis, turrita, longitudinaliter jdicala, spira- 

 liter sulcata, irregular iter vuricosa ; anfractibus plus 

 winusve rotuudis ; nperlnrd rotunda, colmnelld tor- 

 iud, brevi, canali circulari, bremssimo, labro expaiao, 

 sinuoso, ante canalem product 0, rotunda; operculo ro- 

 tunda, cameo, multispirati. 



Shell pyramidal, turreted, longitudinally plaited, spirally 

 sulcated, irregvdarly varicose ; whorls more or less 

 rounded ; aperture round, columella tortuous, short, 

 canal circular, very short, outer lip expanded, sinu- 

 ous, produced in front of the canal, rounded ; oper- 

 culum round, horny, multispiral. 



The mollusca belonging to this genus are amphibious 

 in their habits. They frequent the mouths of rivers and 

 the neighbourhoods of brackish water in mangrove swamps, 

 crawling on stones and leaves, in various localities in dis- 

 tant parts of the world. Panama, Natal, China, Borneo, 

 Australia, and the Philippines, with other places, are tri- 

 butaries to this group. The shells of the various species, 

 when placed together, have a generally conformable ap- 

 pearance, although it is difficult in this, as in other eases 

 among these small generic divisions, to fix upon any one 

 constant definable term of distinction. The columella is, 

 however, always short and tortuous, the canal forms a 

 semicircular sinus, with the expanded outer lip produced 

 in front. 



Species 1. (Fig. a, h, Mus. Cuming.) 



Cekithidea albo-NODOSA. Cer. testa pyramidatd,crasM, 

 distanter et valide varicosd, subglaucd, cancellald; an- 

 fractibus nuinerosis su!)rotundis, varicibus crassis, al- 

 bis ; aperturd subquttdratd, labro crasso. 



The white-variced Cerit?iidea. Shell pyramidal, 

 thick, distantly and strongly varicose, somewhat 

 glaucous, cancellated; whorls numerous, rounded, 

 varices thick, white ; aperture rather scpiare, outer 

 lip thick. 



Carpenter. 



Hab. ? 



Although much narrower than CeritJiidea varicosa, with 

 white varices, this may be only a variety of the latter. 



Species 2. (Mus. Cuming.) 



Ceuithibea Lafonuii. Cer. testa tenui, pnllide cceru- 

 led, ItEvi, brevi; anj'radibus rnluudatis, uiidatim longi- 

 tudinaliter costatis, ad suturam et infra S'dcatis ; aper- 

 turd rotunda, fusco taniatd, labro planutatim, expanao, 

 antice sinuoso, pruduolo. 



Lafonu's Cekithidea. Shell thin, pale-bluish, smooth, 

 shon ; whorls rounded, with waved longitudinal ribs, 

 sidcatfd at the suture and beneath ; aperture round, 

 banded with brown, outer lip fiatly expanded, sinu- 

 ous, produced in front. 



MlcHADD, Kiener, Sp. Gen. Coq. pi. 34. f. 3. 



Ilab. Jamaica. 



A smooth shell, with larger whorls than C. roslala, with 

 which it is associated in Mr. Sowerby's monograph. 



Species '3. 



Cerithidea tenuis. Cer. tesld tenui, turrita, fmcd: 

 anfractibus rotundis, numerosis, longitudinaliter leoiter 

 plicatis, spiraliter ad suturam et infra castatis, superne 

 strialis, costis nodosis ; aperturd rotunda, niargine re- 

 Jlexd. 



The thin Cerithidea. Shell thin, turreted, brown; whorls 

 round, numerous, longitudinally lightly plaited, spi- 

 rally ribbed at and beneath the suture, and striated 

 above, ribs nodose ; aperture round, margin re- 

 flected. 



Pfeiffer. 



Hab. ? 



Differing from C Lafondii in being striated, and in the 

 thin ribs being nodose. 



Species 4. (Fig. a, b, Mus. Cuming.) 



Cerithidea obtusa. Cer. testa venlricosd, spiraliter 

 sulcata, longitudinaliter cosfatd, costis noduliferis, si- 

 uuosis ; anfractibus rotundis, inflatis, ultimo infra 

 angulato, striata, labro valde expanso subplanulato, 

 ante canalem producto, apice frequenter deciduo. 



The obtdse Cerithidea. Shell ventricose, spirally 

 grooved, longitudinally ribbed, ribs noduliferous, si- 

 nuous ; whorls round, inflated, the last angular and 



Mav, 1806. 



