HYALINIA FULVA CHERSINA. 125 
Hyalinia fulva chersina Say. 
Flelix chersina Say, Journ. Acad. Nat. Sci. Phi'ad., 1821, vol. ii., p. 156. 
Conulus chersinus Pilsbry, Nautilus, 1899. p. 116. 
HIS ancient race of Hyalinia fulva is 
dedicated with feelings of profound 
respect to Mr. Thomas Say, the pioneer in 
American conchology, and author of numer- 
ous papers upon the shells of North 
America, who flourished during the early 
part of the nineteenth century, and who 
even at that primitive period in conchology 
discriminated between the //. /ulva and 
the //. chersina, distinguishing the former 
as Helia egena. 
As distinguished from the typical H. fulva, 
H. chersina is deseribed by Pilsbry as very much 
elevated, the height in fully-grown examples 
exceeding the diameter, the general form being 
compared to that of an immature Cerion; spire 
quite convex ; whorls 65, narrower, more slowly 
increasing and more closely coiled than in fudva, 
the last only faintly angular, though carinate in 
young shells ; the base is qnite convex, and the 
wubilicus very narrowly open. Aperture Innate. 
Diam., 2°8 mill. ; alt., 3 mill. 
Dr. Pilsbry, the eminent American malacolo- 
— gist, believes fulva and chers/‘na to be really 
distinet, and although both species inhabit the 
Nearctie region, he hitherto has found no doubt- 
ful or transitional forms among the thousands he has examined, but as this view 
has not yet been confirmed by the demonstration of structural differences, it has 
been thought best to regard H. chersina as an earlier or more primitive form of 
H. fulva, a view which its geographical distribution distinetly confirms, as the 
typical chersina is, according to Pilsbry, apparently restricted to the extreme 
southern part of the Eastern United States, being bounded on the north and west 
by the range of Helix egena of Say, which he regards as identical with the 
European H. fulva. 
The JAW or mandible is small and Fic. Le 
aa d . : ee ex or jaw Oo « Chersina 
delicate and described as arcuate, with (greatly enlarged) aint 
attenuated and recurved ends, anterior Maine: UiStAe tafter 
surface quite smooth, with the concave Morse). 
cutting margin projecting in the centre and forming a rounded beak or rostrum. 
Mr. W. G. Binney records a considerable difference in the dentition according 
to the observations of different investigators. Morse gives the formula of /. 
chersina as 114+7+14+7+11; while Binney, under the name of H. fudva, states the 
formula to be 22+8+1+4+8+22. This great discrepancy would appear to indicate 
that different forms were under examination. . 
idly aaaeacanern"”" 
Fic. 172. Fic. 173. 
Fic. 172.—Mid-tooth, with representative lateral and marginal teeth of Hyadinia /ulva Binney 
(highly magnified) from Orono, Maine (after W. G. Binney). Formula 22+8+1+8+22. 
Fic. 173.—Half a transverse row of the teeth of 7. chersina Morse (highly magnified) from Maine, 
U.S.A. (after Morse). Formula 8+7+1+7+8. 
The range of the true H. chersina has not yet been definitely ascertained, but 
in one or other of its forms it has been demonstrated to exist in the province of 
Ontario in British North America, and in Alabama, Arkansas, Carolina North 
