EASTERN PROVINCE SOUTHERN REGION SPLCIES. 377 



by an elevated, heavy, tooth-like triangular fold. Greater diameter 15, 

 lesser IS""" ; height, 4"""'. 



Polygyra septemvolva, Say, Journ. Acad. Nat. Sci. Phila., i, 278(1818); Nich. Encycl., 

 ed. 3 (1819); BiNNEY'sed., 11.— Tryon, Am. Journ. Couch., iii, 159 (1867).— 

 W. G. BiNXEY, Terr. Moll., v, 281. 



Helix septemvolva, Binney, Terr. Moll. U. S, ii, 196 (part), pi. xxxviii, outer figs. ; 

 pi. xxix, fig. 1.— De Kay, N. Y. Moll., 47 (1843).— Bland, Ann. N. Y. Lye, 

 vii, 131, fig. ou p. 136.— W. G. Binney, Terr Moll., iv, 89, part; L. & Fr.-W. 

 Sh., i, 104 (1869).— Pfeiffer, v, 419 (1868). 



f Helix volvoxis, Pfeiffer, see below. 



Saint Augustine and Key West, Fla. Confined to the Florida Sub- 

 region. 



Animal (see p. 3G0) brownish, eye-peduncles darker, very long and 

 slender, eyes black ; foot narrow, thin, semi-transparent, receiving its 

 color in some degree from the substance on which it is placed, not 

 projecting behind the shell when in motion; length less than twice the 

 breadth of the shell, which it carries nearly horizontal. 



The shell described and figured above, which is no doubt the form 

 called septemvolva by Say, was iound by him at Saint Augustine, Fla. 

 There are, however, associating with it there, and also found at 

 manj^ other points on the Georgia, Florida, and Alabama coasts, other 

 forms which appear to be varieties of it. It may be said, theiefore, 

 that it varies in being occasionally a little convex, more or less carinate, 

 and in exhibiting a greater or less number of full volutions on the base. 

 The lower surface is sometimes marked with the alternate white and 

 brown flammules which characterize P. Carpenteriana. 



The reflected peristome in this shell seems to be formed at various 

 periods of growth, thus creating a greater diversity of size in the ap- 

 parently mature shell than exists in any other species. From the nu- 

 cleus until the accomplishment of five full whorls, each whorl on the 

 base is curved a little lower than that which precedes it ; and up to this 

 time, consequently, the umbilicus is deep and gradually expanding, ex- 

 hibiting, when carefully examined, all the volutions. Up to this period, 

 also, the spire is almost always prominent. After five whorls are com- 

 pleted, the succeeding ones usually follow in the same horizontal plane 

 and give a discoidal character to the shell. It is manifest, therefore, 

 that specimens in each of these stages must present considerable dif- 

 ferences ; and, accordingly, the small, delicate shell, having a slightly 

 convex spire of five whorls, a deep umbilicus, and a transverse diameter 



