114 GASTROCOPTA, EUROPE. 



ized to have been directly ancestral to the American. It ap- 

 pears likely that the European species of Albinula were de- 

 rived from Asia in early Oligocene times, together with 

 Sinalbinula (didymodonta group) and many other land shells, 

 rather than that the Asiatic and American forms came from 

 Europe. It is remarkable that Albinula, while it gave off 

 numerous mutations, changed very little from the Middle 

 Oligocene to the Pliocene, where G. dupuyi and G. fossanensis 

 surely differ but little from the earliest known European 

 Albinula, G. quadriplicata. Whether the Albinula group 

 arose in Asia or North America is an open question at present. 

 It was certainly a mature group at the time of its first known 

 appearance in Europe. 



The other groups of European Tertiary Gastrocopts belong 

 to the Asiatic section Sinalbinula, so far as I can determine 

 from the literature and a few specimens. Some of them, 

 such as the Upper Oligocene G. fissidens Sandb., have the three 

 lamellae of the parietal wall well separated, as in the recent 

 G. chichijimana and ogasawarana, which seem to be ancient 

 forms, preserved by their isolation. Other and later species, 

 such as G. baudoni, from the Pliocene of Hauterive (pi. 21, 

 figs. 13, 14) have wholly concrescent angular and parietal 

 lamella? and no infraparietal, and resemble very closely the 

 recent G. coreana in all structural characters. Whether 

 G. baudoni is an advanced descendant of G. obstructa, or has 

 more direct relations with Asiatic forms due to later migra- 

 tions, cannot now be determined. Recent representatives of 

 the same group (Sinalbinula) are G. pleimesi of Abyssinia 

 and G. theeli of Trans-caucasus. Both are known to me only 

 by descriptions and figures, the latter too small to be any use 

 in the study of phylogenies. 



Subgenus ALBINULA (See p. 13). 

 Series of G. quadriplicata. 



46. GASTROCOPTA QUADRIPLICATA (Al. Braun). Pupa quad- 

 riplicata AL. BR., in Walchner's Geognosie, 2. Aufl., (1851?) 

 p. 1135. Leucochilus quadriplicatum (Al. Br.) BOETTGER, 



