HYALINIA HELVETICA. 5| 
them possessed radulw bearing 87-45 transverse rows of teeth, with an 
average of about 41; the average size of the radula was 2°3 « 0°53 mill., 
the average number of marginal teeth on each side was 11'1, and the space 
occupied by ten rows was 0°56 mill. 
The few specimens examined of the more narrowly perforate typical 
form from Anglesey and Northampton possessed radulie bearing only 
31-38 transverse rows, with an average of 34; the average size ‘of the 
radula was 1'7 x 0°45 mill.; the average number of marginal teeth on 
each side was 10°6, while the space occupied by ten rows of teeth was 
05 mill. 
Specimens from Hochwald, Austria, recorded as Zonites glaber vay. 
striaria by Prof. Cockerell, are in his opinion certainly the Zonites glaber 
of Jeffreys, resembling the Cheshire rather than the South of England forms. 
He described them as of a transparent yellowish-horn colour, very shin- 
ing and flattish ; aperture more semi-lunar than usual; umbilical region 
hardly whitish. Max. diam., 114 mill. 
Messrs. Moss and Boycott, who received specimens under the same name 
through Dr. Babor, remark, however, that the animals examined by them 
showed the dental characteristics of the true Hyalinia glabra, and not 
those of //. helvetica. 
7 VARIATIONS IN SHELL. 
Var. umbilicata var. nov. 
SHELL rather larger and more deeply coloured, with a more depressed spire, and 
consequently a more open twinbilicus. Diam., 11 mill. ; alt., 5 mill. 
This is a very striking shell when characteristic, but is connected with the 
typical form by intermediate gradations. 
York Mid W.—Malham Cove, July 1903! J. W. Jackson. 
ENGLAND. 
Var. viridans Cockerell, Science Gossip, 1885, p. 226. 
Zonites glaber var. viridula Adams, Journ. of Conch., 1890, p. 265. 
SHELL transparent and greenish-white. 
ENGLAND AND WALES, 
Dorset—Portland, Aug. 1892! Lionel E. Adams. 
Kent W.—Iour specimens with type on a bank at Bromley (Cockerell, |.c.). 
Northampton—Castle Ashby, June 1906, Rey. W. A. Shaw. 
Cheshire—Near Warrington, March 1906, J. Whitwham. Disley, 18938, and 
Marple, 1894, K. H. Jones. A greenish variety at Oakwood (J. W. Jackson, Journ. 
of Conch., July 1903, p. 336). Sparingly at Romiley, 1903, J. W. Jackson. 
York S.W.—Bramley lall Wood, Nov. 1889 (If. Rhodes, Sci. Goss., Aug. 1890, 
p. 190). Buek Wood, Thae tkley, 1890, A. Hartley. Gunthwaite near Penistone, 
April 1890 ! Lionel E. Adams. 
Kerry—Kenmare, 1898! RK. Welch. 
IRELAND. 
Var. bicolor Cockerell, Science Gossip, Jan. 1886, p. 20 
SHELL with whitish basal opacity well marked and sharply defined from the 
brown colour of the rest of the shell. 
The author views this variety as atavie. 
ENGLAND 
Kent W.—Bromley (Cockerell, 1.c.). 
Geographical Distribution.—Owing to the confusion which has 
reigned in regard to the identification of this species, its range abroad 
is almost unknown : it has, however, been authentically reported from 
Switzerland, Germany, Irance, and Belgium, and probably also exists in 
inany other countries. The Zonites glaber var. striaria, inhabiting ‘Tran- 
