MARSHALL: ADnillONS TO "BRITISH CONCHULOGY. 33I 



Live specimens are opaque, but when picked out of shells and are 

 glossy and transparent, sometimes ornamented with spiral pellucid 

 zones ; in this state, according to Monterosato, it is U'. semisulcatus 

 Phil. The same peculiarity is apparent in U. tornatiis Wats., from 

 the Azores and Tenerife and various other places. Specimens from 

 Limfjord are encircled with several constricted spiral lines, and this is 

 occasionally observable in British examples. The very young are oval, 

 and the upper corner of the aperture projects over the embryo prepara- 

 tory to enclosing it. In the adult stage the length of the aperture 

 varies considerably. Two abnormal specimens from Guernsey, 2of., may 

 prove to be a new species or monstrosities of this one ; they are 

 oblong in shape, the apical nipple is larger, level with and filling up 

 the crown, and the other whorls are invisible; they are somewhat 

 similar in these respects to U. tornatus Wats., but are larger, while 

 only the longitudinal lamellae connect them with U. trimcatulus. 

 Another form from Guernsey is regularly cylindrical, which island also 

 yields the finest examples. I have examined many living specimens 

 without detecting the operculum with which Professor Loven credits 

 this species. 



var. pellucida Brown. — Castle Bay, Barra, in shallow water, and 

 in the Minch off Barra 2o-3of. (Somerville and J.T.M.). This variety 

 is usually smaller, shorter, and cylindrical, and resemble some of the 

 forms of U. obtusus ; but the Castle Bay specimens are very much 

 larger (two lines by one), and instead of being cylindrical or con- 

 stricted in the middle, they gradually enlarge from the apex down- 

 wards, forming an oval cone similar to the British figures of Cylichna 

 conulus, for which they might be easily mistaken, but the crown is 

 different. 



U. obtusus Mont. — The distribution of this species and its 

 varieties is very extensive : "From Spitzbergen to the Adriatic, and all 

 along the eastern coasts of N. America from Wellington Channel to 



Cape Cod Its habitat ranges from low-water mark to 



114 fathoms, and it especially frequents brackish water" (Jeffreys).^ 



var. lajonkaireana Bast. — Not confined to the Shetland and 

 Channel Islands, though most plentiful in those groups. Scilly 

 (Smart and others) ; Southport, Skegness, Killala Bay, Dublin Bay, 

 Portmarnock, Portrush, lona, and Barra. Fossil with the type in 

 the Belfast deposit, where a monstrous form occurs in which tlie spire 

 is as long as the aperture (Praeger) ! 



var. minor Jeff., Med. Moll., Ann. Mag. N. Hist., 1870, p. 20, 

 sep. cop. — -"Apice depresso." L. o'o6 in., b. 0*04. This is a re- 

 duced facsimile of the large estuarine form, and occurs frequently 

 at Guernsey in 15-22^, and sparingly at Scilly in 30-4of. In the 



I New and Peculiar Moll., Ann. Mag, N. Hist. 1S77, p. 334. 



