FAMILY COLIMACEA. Ill 



mollusk have been exercised more vigorously than usual in the 

 secretion of superficial sculpture are invariably smaller than speci- 

 mens of the same species in which any kind of decorative sculpture 

 is avoided. Granulated varieties of Cones, for example, are always 

 smaller than smooth varieties of the same species. It is the same 

 with Pupa muscorum. When there is no tooth or callosity, the 

 whorls are of a fighter substance and more tumid growth. In either 

 case they are narrow, increasing but slowly on one another, and 

 forming an unusually straightly cylindrical chrysalis-like shell. 



The animal of Pupa muscorum, as might be expected in a narrow- 

 whorled shell, is rather slender. In colour it is dark leaden blue, 

 obscurely lineated and speckled. It is generally distributed through- 

 out the British Isles, more particularly in chalky districts ; and it 

 is equally universal on the Continent, reaching in the north to Ice- 

 land, Lapland, and Siberia, and in the south to Sicily. 



3. Pupa cylindracea. Cylindrical Pupa. 



Shell ; shortly cylindrical, rather conspicuously umbilicated, olive- 

 brown, transparent horny, whorls six, rather 

 tumidly convex, scarcely striated, last whorl 

 rather large in proportion to the others ; 

 aperture small, triangularly ovate, with a 

 single parietal tooth on the body-whorl, 

 tooth sometimes nearly obsolete, lip broad, 

 whitish, callously, flatly expanded, some- 

 times swelling a little inwardly. 



Turbo cylindraceus, Da Costa (1778), Test. Brit. p. 89. pi. v. f. 16. 



Bulimus muscorum, pars, Bruguiere (1789), Enc. Meth. Vers, vol. i. p. 334. 



Pupa umbilicata, Drapamaud (1801), Tabl. Moll. p. 58. 



Bulimus unidentatus, Vallot (1801), Exerc. d'Hist. Nat. p. 6. 



Turbo muscorum, Montagu (1803), Test. Brit. p. 335, Supp. pi. xxii. f. 3 

 (not of Linnaeus). 



Odostomia muscorum, Fleming (1814), Edin. Encyc. vol. vii. pi. i. p. 76. 



Helix ( OochlodontaJ umbilicata, Ferussac (1822), Tabl. Syst. p. 59. 



Jaminia muscorum, Bisso (1826), Hist. Nat. Europ. Merid. vol. iv. p. 88. 



Pupilla Drapamaudii, Leach (1831), Turt. Man. p. 126. 



Pupilla umbilicata, Beck (1837), Ind. Moll. p. 84. 



Pupa Sempronii, Charpentier (1837), Moll. Suiss. p. 15. pi. xi. f. 4. 



Eruca umbilicata, Swainson (1840), Treat. Malac. p. 334. 



Stomodonta umbilicata, Merniet (1843), Moll. Pyr.-Occid. p. 53. 



