CEEITHIUM.— Plate XX. 



A small, delicate-white species, with the whorls tuber- 

 culated in three rows. 



Species 146. (Mus. Cuming.) 



Cerithium SEK0TINU5I. CeritJi. testa aoUdd, oblungo- 

 cylindraced, pnlUde fulvd ; anfractibus brevihtts, tm- 

 merosis, longUudinaliter crebri-plicatis, spiraliter dri- 

 atis, medianis siibventricosis, ultimo subconlracto, 

 iruncato ; aperturd subqitadratd, lateruliter productd, 

 columelld laminatd, margine extanie, canali oblongo, 

 Iruncato. 

 The evening Cerithium. Shell solid, oblong-cylin- 

 drical, pale-fulvous ; whorls short, numerous, longi- 

 tudinally closely plicated, spirally striated, those of 

 the centre rather ventricose, the last slightly con- 

 tracted, truncated ; aperture rather square, laterally 

 produced, columella laminated, with margin standing 

 out, canal obloug, truncated. 

 A. Adasis, Son-erby's Thes. Conch. Cerithium, sp. 48, 



f. 102. 

 Hab. Van Diemen's Land. 



There are peculiarities in this species and C. rJwdostoma 

 of almost generic value, among which the free lamina 

 composing the columella, the constricted canal-tube, and 

 the contraction and truncation of the last whorl may be 

 mentioned. 



Species 147. (Mus. Cuming.) 

 Cerithium clathratum. Cerith. testa alba, pyrami- 

 datd, scalatd; anfractibus iiovem, ventricosis, spira- 

 liter bicostatis, longitudinaliler pUcatis, costis promi- 

 nenlibus, plicis frequeniilus, lamelliformibus, monili- 

 feris ; ultimo anfractu subtus angulato, ad angulmn 

 costd duplicatd cincto ; aperturd subquadratd, colu- 

 melld brevi, canali brevi, aperto. 

 The cross-barred Cerithium. Shell white, tapering, 

 rising in steps ; whorls nine, ventricose, spirally two- 

 ribbed, longitudinally plaited, ribs prominent, plaits 

 numerous, lameUated, beaded; last whori angular 

 beneath, girt at the angle with a double rib ; aperture 

 rather square, columella short, canal short, open. 



A. Adams, Sowerby's Thes. Conch, sp. 152. f. 258. 

 Hab. Baclayon, Island of Bohol, Philippines. 



Species 148. (Mus. Cuming.) 



Cerithium excavatum. Cerith. testa pyramidatd, spi- 

 raliter striatd, albd ; anfractibus numerosis, superne 

 ad suturam costd minute tuberculatd ornatis, infra 

 medium angulatis, ad angulum tuberculis validis ar- 

 matis, infra ad sufu?-am uniliratis, supra angulum ex- 

 cavatis ; aperturd rhomboided, columelld tenui, canali 

 vix emarginato. 



The excavated Cerithium. Shell pyramidal, spirally 

 striated, white ; whorls numerous, ornamented above 

 at the suture with a minutely tuberculated rib, below 

 the middle, angular, at the angle armed with strong 

 tubercles, beneath, at the suture, one-ridged, the last 

 double-ridged, above the angle hollowed ; aperture 

 rhomboidal, columella thin, canal scarcely emargi- 

 nated. 



SOWEKBY. 



Ilab. North Australia. 



Species 149. (Mus. Cuming.) 



Cerithium obesulum. Cerith. testd brevissimd, ventricosd, 

 solidd, nigrescenle ; anfractibus paucis, supra medium ad 

 dorsum angulatim subelevatis, spiraliter costis monili- 

 feris cinctis, ultimo magno ; apirturd albidd, magna, 

 columelld brevissimd, canali brevi, subconlracto, labro 

 intns crenato. 



The little fat Cerithium. Shell very short, ventri- 

 cose, solid, blackish ; whorls few, above the middle 

 at the back angularly slightly elevated, spirally girt 

 with beaded ribs, the last large; aperture whitish, 

 large, columella very short, canal short, slightly con- 

 tracted, outer lip crenated within. 



SOWERBY. 



Hah. ? 



In form resembling C. obesum, being slightly raised and 

 bossed at the back, in the same manner as is seen in that 

 species and in C. chrsuosum. It is however distinguished 

 by beaded ribs, and is of a dark, almost black, brown 

 colour. 



