254 



A MANUAL OF AMERICAN LAND SHELLS. 



Fig. 267. 



ting points even in the same lingual membrane, but as a general thing 

 it may be said that the marginal teeth are but a modification of the 

 form of the laterals. They decrease in size greatly at the outer edge of 

 the lingual membrane. 



It must be borne in mind that the cutting points vary in develop- 

 ment on difi'erent portions of any one lingual membrane. I have in 

 each case chosen for drawing such individual teeth as appear best to 

 illustrate the general character of the dentition (in Terr. Moll., V). 



It will be seen that Patula differs from all the genera of Limacidw 

 and Agnatha by the presence of quadrate, not aculeate, marginal teeth, 

 a character shared by all the succeeding genera. There does not appear 

 any very essential character in the dentition by which to distinguish it 

 from manj' of the other American genera of disintegrated Helix, as will 

 be seen below. It will be noticed that one species, asteriscus, has mar- 

 ginal teeth like those of Pvpa and Vertigo. 



Patula solitaria, Say. 



Shell broadly umbilicated, globosely depressed, coarse, solid, diaph- 

 anous, obliquely arid crowdedly wrinkled, from 

 white to dark-reddish horn-color, with from two to 

 three brownish revolving bands : whorls 6, con- 

 vex ; suture deep ; aperture roundedly lunate, 

 pearly white and banded within ; peristome sim- 

 ple, acute, its ends joined by a thin, transparent 

 callus, that of the columella dilated, subreflected. 

 Greater diameter 25, lesser 22'"'" ; height, 15'""'. 



Helix solitaria, Say, Journ. Phila. Acad., ii, 157 (1821); Binney's ed., 19.— De Kay, 

 N. Y. Moll., 43, pi. iii, fig. 41 (1843).— Binney, Bost. Journ. Nat, Hist., iii, 

 426, pi. xxii (1840) ; Terr. Moll., ii, 20«, pi. xxiv.— Chemnitz, ed. 2, i, 180, 

 pi. xxiv, figs. 5, 6.— Pfeiffer, Symbolae, ii, 39; Mon. Hel. Viv., i, 102. — 

 Reeve, Con. Icon., 662 (1852).— W. G. Binney, Terr. Moll., iv, 96.— Leidy, 

 T. M. U. S., i, 254, pi. viii, figs. 7-10 (1851), anat.— W. G. Binney, L. & Fr.- 

 W. Sh., i, 71, fig. 119 (1869). 



Anguispira solitoria, Tryon, Am. Journ. Conch., ii, 260(1866), 



Patula solitaria, W. G. Binney, Terr. Moll., v, 156. 



Microscopic revolving lines have been detected on some specimens. 

 There is a form of a dark reddish-brown color, with 

 one white band at the periphery, and the same color 

 at the base around the umbilicus. Albino forms are 

 also found (see Fig. 268). 



The Museum of Comparative Zoology has a reversed 

 specimeu, 



p. solitaria. 



Fig. 268. 



Vftr, dl^im, 



