A N A 8 T U A . 



Plate 1. 



Genus ANASTOMA, Fischer. 



Tesia depress? globosa, leidicularis, anfraclu ultimo abnpti 

 iraiisvolulo, aferlurd sendlunari, supra spirani reversa, 

 utrinque iniro denlatd, dentibus plicato-laudualis, ex- 

 terioribus quatiior ad quinque, columellaribus duobus, 

 labro expanso-rejlexo, interdum superne perforata. 

 Shell (lepvessly globose, lens-shaped, last whoii abruptly 

 turned aeross, aperture semilunar, turned upwards to- 

 wards the spire, toothed within on both sides, teeth 

 plicately laminate, outer teeth four to tive, columellar 

 teeth two, lip expandedly refleeted, sometimes per- 

 foi'ated at the upper part. 

 It is a curious feature in the natural history of Brazil 

 that that country should g-i\'e birth to a form of snail dif- 

 fering from all other snails in a habit of reversing the po- 

 sition of its shell on arriving at maturity. Up to the for- 

 mation of the first half of the last whorl the growth of 

 the sliell proceeds as usual, but from this point the whoi-1 

 is suddenly tiu-ned across in the direction of the apex. Bv 

 this new effort of the animal the shell is overturned, and 

 the apertiu-e is brought on a plane with the spire. The 

 snail thenceforward crawls with its spire downwards, and 

 base upwards. Two very distinct species of Anastoma 

 were known to Fcrussac and Lamarck, A. rhujeus and 

 globulosum, the first having been known to Liiinajus. 

 Three more species have been added by modern writers, 

 but they are of much inferior value. A. Desliaijesiaiium and 

 Verreauxinnum differ little from .-/. rhujens ; and A. cari- 

 natum is probably only a variety fif A. (jhibulosam. 



Species 1. (Fig. a, b, Mus. Cuming.) 



Anastojia carinatum. Aiiast. testa orbicularis Jcpres- 

 siusi'uJd, ad periplieriam plus viinus aiiijulalo-varinatd, 

 livido-olimceu, supra peripheriam ustulato-purpureo 

 fasciatd, infra pnrpureo-rufo maculate!, avfractibtis 

 supra concenlrice arcuato-slriatis, infra reticulato- 

 corruijatis, labro superue perforata. 



The keeled Anastoma. Shell orbicular, rather de- 

 pressed, more or less angularly keeled at the peri- 

 phery, livid olive, banded above the periphery with 

 burnt-purple, beneath spotted with purple-red, whorls 

 concentrically arcuately striated aliove, reticulately 

 wrinkled below, lip perforated above. 



Pfeiffek, Pro. Zool. Soc. 1853. p. 57. 

 Hab. Brazil. 



This and A. (jlobulosum, which are probably varieties of 

 one and the same species, are curiously characterized by 

 the lip being perforated at its upper junction with the 

 body whorl. 



Species 2. (Fig. c, b, Mus. Cuming.) 



AXASTOJIA GLOBULOSUJI. Auasl. testd dt-presso-fflobosd, 

 ad peripheriam unnc rotniiJatd, nunc subcarinatd, 

 lioido-oUi-nced, supra peripheriam ustulato-purpureo 

 fa.viatd, iufra purpurea-rufo leutighiosd, aufractibus 

 supra concentriei' arcualo-striatis, hifra reticulnto- 

 corruyaUs. 



The globular Anastoma. Shell depressly globose, 

 now rounded, now slightly keeled at the jieriphery, 

 livid olive, banded above the periphery with burnt- 

 purple, freckled beneath with purple-red, whorls con- 

 centrically arcuately striated above, reticulately wrin- 

 kled below. 



Lamarck, Anim. sans vert. vol. 8. p. 153. 

 Helix riiigicida, Ferussac. 



Ilab. Brazil. 



The examples set apart for this species are uniformly 

 smaller and rounder than those of the preceding. 



Species 3. (Fig. a, b, JIus. Cnming.) 



Anastoma kingens. Auast. testd depre-iso-orbiculari, 

 subrude tumidd, ad peripheriam s/rpe subcarinatd, al- 

 bidd, rufo-castaneo iuquinatd et maculatd, juxta su- 

 turas fasciatd, supra lavlgatd, infra obscure currur/ato- 

 striutd. 



The grinning Anastoma. Shell depressly orbicular, 

 rather rudely swollen, often slightly keeled at the 

 periphery, whitish, daubed and spotted with reddish- 

 chestnut, banded next the sutures, smooth above, 

 obsciu'ely wrinkle-striated beneath. 



Helix, ringens, Linnaeus, Syst. Nat. p. 13i3. 

 Tomogerus ringens, De Montford. 

 Auostonia depressa, Lamarck. 

 Anostoina ringens, Deshayes. 



Hab. Brazil. 



•lune, ISlio. 



