PULMONATA. 67 



No. 20. Helix labyrinthica. Say. Tab. X, fig. 7 a — e. 



Helix labykinthica. Say. Journ. Acad. Nat. Sc. Philadelphia, vol. 1, p. 124. 



— — Nicholsons Encycl. (Amer. Edit.), 4. 



— — Fcrussac. Hist. Natur. des Moll., tab. li b, fig. 1 ; Prodromus, 



No. iii. 



— — Binney. Boston Journal Nat. Hist., vol. iii, tab. xxiv, fig. 1. 



— — Gould's Report of the Inverteb. of Massachus., p. 184. 



— labyrinthicus. S. Wood. Lond. Geol. Journ., vol. i, p. 118. 



H. testa minima, globoso-conicd, transversim lineatd, umbilicatd ; lineis obliquis, undosis, 

 numerosis ; spird plus minusve elevatd, sexies circumvolutd ; anfractibus convexis ad basin 

 sub-planidatis : aperturd depresso-semilunari, peristomate reflexo : margine columellari uno 

 dente lamelliformi instructo : umbilico magno, prof undo. 



This pretty and very rare Helix is a small, roimdedly-conical shell, with a more 

 or less elevated spire, composed of about six gradually increasing whorls, separated 

 by a clearly defined suture, and ornamented with numerous, elevated, obliquely trans- 

 verse, equidistant, raised lines, more or less prominent in different individuals. These 

 lines are somewhat acute, slightly undulated, and, running into the umbilicus, cover 

 the whole surface of the whorls. The base of the shell is but slightly convex ; the 

 aperture of a depressed semilunar shape, with the peristome reflected. The columella 

 lip presents a large lamelliform tooth, prolonged within the aperture, and running 

 parallel with the suture. The umbilicus is deep and wide, being about one third of 

 the diameter. In one specimen in my cabinet, the spire is very much depressed, 

 almost planorbular, and the apex more obtuse. 



This species derives additional interest from the fact that, having survived through 

 the inconceivably long spaces of time required for the deposit of the Miocene and the 

 more recent formations, and having become extinct in the hemisphere in which it first 

 appeared, it is now found among the living forms of North America. The recent Helix 

 labyrinthica, first described by Say, is spread over a wide range of country, extending 

 from Ohio to Florida, and from Missouri to Texas. Specimens from Texas, Ohio, and 

 Florida are preserved in the British Museum ; and, after a careful comparison with 

 them of the fossil shells, it appears to me that differences of sufficient importance for 

 specific distinction cannot be detected between them ; I therefore fully concur with 

 Mr. S. Wood in the opinion expressed by him of their specific identity, and I do not 

 hesitate to refer the fossil shell to Say's species. 



In order to facilitate an examination into this identity, it will be useful to give 

 Say's description in his own words. It is as follows : " Shell conic, dark reddish- 

 brown ; body lighter ; whorls five or six, with conspicuous, elevated, equidistant, 

 obtuse lines across, forming grooves between them ; apex obtuse ; lip reflected, 



