225 



Asia to the opposite shores of North Africa. At the eastern limit of this 

 province in the British Isles and at the western limit, in the Meia-co-shiinah 

 Isles, the shell is of the same form, substance, and colour. The shell of 

 the Caucasian Bulimics is small, mostly white or dusky brown, sometimes 

 convoluted sinistrally, and partakes very much of the character of Pupa, 

 which is the predominant genus of this district. At the north-western ex- 

 tremity of the Caucasian province the genus is represented in the British 

 Isles, Germany, France, Spain, and Portugal by the small B. obscurus, 

 montanus, and acutus. The first of these extends to South Sweden, fifteen 

 to twenty degrees nearer the Arctic Circle than in the new world, agree- 

 ably with the curve of Humboldt's isothermal lines in that direction, illus- 

 trative of the warmer comparative temperature of this portion of the eastern 

 hemisphere. In B. ventrosus and decollatus the genus obtains a more 

 southern range, extending into Sicily and the Canary Islands. The Bulimi 

 of the Canary Islands are, however, for the most part indigenous. Of the 

 following species inhabiting this group, B. variatus, Moquinianus, obesatus, 

 bceticatus, Bertheloti, subdiaphanus, only the last is found in any other lo- 

 cality, the Cape de Verd Islands. No Canary Island Bulimus has been 

 collected in Portugal, Spain, or Sicily, but a species has been found to 

 range along with B. barbarus, rupestris, and Bergeri over Greece and the 

 eastern islands of the Mediterranean to Algeria and the borders of Egypt. 

 B. detritus, subtilis, and quinquedentatus may be noted as belonging more 

 especially to Austria and Central Europe, and B. Farnensis, Frivaldskyi, 

 and C/iersonesicus to Turkey and the Crimea. Towards the vicinity of the 

 Caucasus the Bulimi are more numerous, of larger and more solid growth, 

 and more divided into groups. Owing to the dry juiceless thorny cha- 

 racter of the vegetation, their habits differ from those of the humid and 

 woody countries of intertropical America. Their shells are comparatively 

 small, with little colouring matter or epidermis, and they live under stones 

 or blocks of wood, or suspended for a long season in a state of torpidity 

 from the shrubs. The difference between the shell of the Caucasian and 

 that of the Malayan or Venezuelan Bulimi is very characteristic of the 

 physical conditions with which the animal is surrounded in each instance. 

 B. labrosus, labiosus, Alepi, Sgriacus, and Ehrenbergi are true Caucasian 

 types. In B. Sprattii and Lycicus the shell has a light and ventricose 

 growth, but in B. spoliatus, zebriolus, and Toumefortianus it has an elon- 

 gated Pttpa-\ike form. 



Passing the south-western countries of Asia we find no species of Buli- 

 mus recorded from any locality between Syria and Afghanistan. Of the 

 terrestrial conchology of Persia, Tartary, and Beloochistan, nothing is at 

 present known, and very little of that of China. South of Syria a natural 

 boundary is imposed to the range of the genus in that direction by the 

 rainless and riverless deserts of Arabia. A few species make their appear- 



2 G 



