272 CERITHIOPSID^E. 



Scacchi); Bona, among coral-refuse (Tiber!) ; Algiers 

 (Weinkauff) ; ^Egean (Forbes); Pantellaria, Smyrna, 

 Madeira, and Orotava in the Canary Isles (M f Andrew) : 

 depths 7-60 f. 



It may be known from every other British species of 

 Cerithiopsis by its extremely elongated spire, narrow 

 shape, muricated sculpture, having five spiral ridges on 

 the last whorl and four on each of the preceding ones, 

 and by the whorls being convex and rounded. 



The synonyms are Cerithium angustissimum, Forbes, 

 C. creperwn and C. cribrarium, S. Wood, C. angustinum, 

 M f Andrew, and C. Crosseanum, Tiberi. 



\-t\* 5. C. cosTULA'TA*,\Moller.) 



Turritella? costulata, Moll. Ind. Moll. Qroenl. p. 10. 



SHELL resembling in shape a slender obelisk, solid, semi- 

 transparent, and glossy : sculpture, curved, sharp, and promi- 

 nent longitudinal ribs ; there are about 16 on the body- whorl, 

 which are cut off at the periphery by a spiral ridge, giving the 

 base an angulated appearance ; the ribs are traversed and in- 

 dented by thread-like impressed lines or striae (3 on the body- 

 whorl, and 2 or 3 on each of the other whorls), besides finer and 

 slighter intermediate striae in the interstices of the ribs as well as 

 on the base ; the latter (which is somewhat excavated) is encir- 

 cled by a narrow ridge ; the second whorl from the apex is closely 

 striated lengthwise, the first being smooth : colour white : 

 spire finely tapering ; the terminal part is very slender in pro- 

 portion to the rest of the spire ; the point is blunt, and obliquely 

 twisted inwards : whorls 12, rather convex, the last occupying 

 about one-third of the shell : suture wide and deep : mouth 

 small, roundish-oval, slantingly truncated at the base ; its 

 length, compared with that of the spire, is only as 1 to 6 : 

 canal short, wide, and open, ending in a deep notch at the 

 base : outer lip curved and slightly inflected ; edge and inside 

 smooth ; upper side not contracted : inner lip rather slight, 

 reflected on the pillar, and continuous with the outer lip at 

 the upper corner of the mouth : pillar curved. L. 0-4. B. 0*1. 



* Slightly ribbed. 



