MARSHALL : ADDITIONS TO BRITISH CONCHOLOGY. I95 



finely tapering spire, with a plicated but not tubercular throat." ^ 1 

 think this must be erroneous. I have met with colonies of 

 long-spired and also of short-spired forms, sometimes mixed and 

 sometimes isolated. There is a colony of the long-spired form now 

 at Torquay which cannot all be males, and, moreover, their apertures 

 are both plain and tuberculated, none of them plicated. I have 

 looked over many groups of these molluscs, but have never been 

 able to pick out the male from these outward characteristics. The 

 tuberculations of the aperture are periodical marks of growth, and 

 not of maturity. 



var. imbricata Lam. — This is a scarce variety, and very local. 

 Ordinary imbricated or fimbriated specimens are not uncommon, 

 chiefly from quiet bays where there is no surf, or from rocks rather 

 low down the littoral zone. (There is one colony of them at Fleet- 

 wood, and another at Cleethorpes.) The young also are frequently 

 fimbriated. But in tlie true var. imbricata the sculpture is flounce- 

 like and about |^in. deep ; it is, moreover, one of the handsomest of 

 British shells, its snowy-white appearance and deep flounces giving 

 it more the appearance of a tropical species than a sober British one. 

 Rarely the shell is fawn-coloured. There is a fine series in the Mac- 

 Andrew collection at Cambridge, one of which is figured in Joiirn. 

 of Conc/i., 1895, vol. viii., pi. iv., fig. 10. It is also well figured in 

 " British MoUusca " (pi. cii., fig. 2) ; but Searles Wood's figure of the 

 Crag form (tab. iv., fig. 6g), as well as Sars' figure of the Norwegian 

 form (tab. 23, fig. 15), are not this variety, but ordinary imbricated 

 specimens. This variety has only once been dredged in any number, 

 and tliat by Mr. MacAndrew in Rhoscollyn Bay, and he parted with 

 his surplus specimens to a shell dealer, who made a " corner " in 

 them and doled them out at famine prices. A client, having seen one 

 of these, wrote for more on approval, and received a fine series of 20 

 at 7s. 6d., of which he was so enamoured that he could not part with 

 them again, but kept the wliole parcel for ^^7 los. ! 



var. ovalis Jord.,y^//r'«. of Co/ic/i., J893, vol. vii., p. 260; and vol. 

 viii., pi. 4, fig. 16. — Paignton in South Devon (Jordan and J.T.M.); 

 Morthoe in North Devon (Cooke) ; Scarboiougii. 



var. major Jeff — Solent and Conway Rivers (Cooke) ; Laugh- 

 arne sands (Williams- Vaughan) ! Swanage. This is very large and 

 coarsely ridged, and the aperture is without the usual tubercles or 

 thickened margin ; the animal appears to prefer using its materials to 

 enlarging its abode than to ornamenting it. Figured \n /ourn. of 

 Cofich., 1895, vol. viii., pi. 4, figs. 5 and 12. 



var. elongata S. Wood, Crag Moll., vol. i., p. 36, tab. 4, fig. 



I Brit. Conch., vol. iv., p. 282. 



