76 VERMETID^E. 



flattened concentric ring-like ribs, which are packed so closely 

 as to allow very little space between them ; they are some- 

 times arranged in joints or interrupted strangulations, denoting 

 probably the limits of successive curtailment ; under a micro- 

 scope the entire surface (especially the interstices of the ribs) 

 is seen to be marked lengthwise by excessively minute and 

 crowded stria3 : colour yellowish- or reddish-brown, occasionally 

 variegated by circles of a darker hue : spire none in the adult, 

 its place at the posterior extremity being closed by a solid 

 shelly plug, which slopes from the ventral margin to a bluntly 

 conical point on the opposite or dorsal side : mouth annular, 

 slightly contracted, and strengthened by the last-formed rib : 

 operculum brown or dark-horncolour, consisting of about a 

 dozen gradually increasing whorls, denned by a narrow raised 

 spiral line or suture ; they become less distinct towards the 

 centre, which is concave. L. O125. B. 0-033. 



HABITAT : Rather common in the coralline zone of 

 Dorset, Devon, and Cornwall; Sandwich (Walker); 

 Guernsey (Barlee) ; Swansea, Tenby, and Barmouth 

 (J. G. J.) ; Bantry Bay (Thompson and J. G. J.) ; Ar- 

 ran Isle, co. Galway (Barlee) ; Clyde district (Norman 

 and Robertson) . I do not consider it a British fossil ; 

 for I believe the shells described and figured by S carles 

 Wood from the Coralline Crag are not this species, but 

 his C. mammillatum. Philippi, however, has given it as a 

 Sicilian fossil, under the name of Odontidium rugulosum ; 

 and Professor Homes includes it in his great work on 

 the Miocene formation near Vienna. It inhabits the 

 coast of Brittany, beyond low-water mark of spring- 

 tides, according to Cailliaud ; M f Andrew dredged it in 

 8 f. at Vigo ; and several authors have noticed it as 

 Mediterranean (both on the European and African 

 coasts) and Adriatic ; on sponges from the Archipelago 

 (Bean); Canary Isles, 50 f. (M f Andrew) ; Cuba (Philippi). 



Clark informs us that the animal is not at all shy, 

 and that all the specimens which he examined had an 

 ovary. He expressed some doubt whether the branchial 



