PUNCTUM PYGMAUM MINUTISSIMUM. 161 
P. pygmeum minutissimum (Lea). 
Helix minutissima Lea, Trans. Amer. Phil. Soc. 1841, ii., p. 82. 
Helix minuscula Binney, Terr. Moll., ii., p. 221. 
Punctum minutissimum Morse, Journ. Portl. Soc., 1864, p. 27 and figs. 
Conulus minutissima Tryon, Amer. Journ. Conch., 1866, ii., p. 257, pl. 4, f. 63. 
Hyalina minutissima Binney. Gould's Invert. Mass., 1870, p. 403. 
Microphysa pygmea Binney, Man. Amer. Shells, 1885, p. 71, ff. 31-33. 
HIS ancient race of Punctum pygmeum is 
the object of great differences of opinion 
as to its exact identity or otherwise with the 
Palearctic form; but as certain concho- 
logical and structural pecuharities have been 
described as characterizing the American form 
which have not yet been controverted, it is 
deemed desirable to recognize its claims to 
racial distinction. 
This interesting Nearctic race is asso- 
ciated with one of the most famous of 
contemporary conchologists, and a leading 
pioneer in the systematic utilization of the 
details of anatomical structure in the discrim- 
ination and classification of species —Mr. 
W. G. Bimey, of Burlington, New Jersey, 
U.S.A., author of many excellent standard 
inanuals upon American conchology, and who, 
during 1874 in conjunetion with the late Mr. 
2 a . Thomas Bland, published a monographie 
/V. - Jo Zr account of the history and structure of the 
present species. 
P. pygmwum minutissimum is said to never attain the dimensions of 
the European P. pygmaum, while the suture is always nearer the centre 
of the body-whorl, and the spire is consequently more elevated; the 
whorls are also more compact and revolve more closely, wluile the 
aperture is more oblique. 
The two forms when highly magnified exhibit faint revolving lines, 
which in P. pygmeeum are more distinct and wider apart ; while the 
prominent transverse strive are also more regularly disposed and wider 
apart in the Enropean form. 
Fic. 219. Fic. 220. PEON Ces rm GF 
Fic. 219.—P. pygmeum (Drap.) magnified, : 2 TA 
Florence, Italy (after Morse). aos 5 ae 
Fic. 220.—P. minutissimum (Lea) magnified, Fic. 221.—Magznified surface sculpture 
Bethel, Maine (after Morse). and cross-section of the body-whorl of 
P. minutisstnium (after Morse). 
‘he shell is described as having the surface of the whorl raised ina 
series of coarse ridges, parallel with the lines of growth, becoming more 
distinct and prominent as the umbilical region is approached, and often 
coalescing at or near their junction with the suture; the fait revolving 
lines also become more prominent near the wnbilicus and appear to be 
arranged in pairs. 
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