112 GASTROCOPTA, EUROPE. 



plicae visible with difficulty even under the lens. Aperture 

 almost circular, somewhat biangular above, rounded below; 

 peristome continuous, somewhat spreading, very little thick- 

 ened. Throat 4-toothed: palatal [= parietal] tooth strong 

 and doubled, the inner part larger, pliciform, the outer 

 smaller, less entering; columellar tooth horizontal; parietal 

 [=; palatal] teeth two, oblique, the lower one larger. A very 

 small tooth in the lower angle of the columella, sometimes a 

 little larger. Color white, hyaline. Alt. 2%, diam. maj. 1%, 

 diam. aperture % mm. (B. & D.) 



Indo-China: shore and islands of the Bay of Along (M. 

 Demange ) . 



Pupa (Bifidaria) ejecta BAVAY et DAUTZENBERG, Journal 

 de Conchyl. Ix, 1912, p. 29, pi. 1, f. 16, 17. 



This species stands very near to Gastrocopta armigerella 

 Reinh., but differs, according to MM. Bavay and Dautzenberg, 

 by wanting an infraparietal tooth, and by the form of the 

 angular and parietal lamellas, which are juxtaposed laterally, 

 not superposed as in armigerella. It was found in the marine 

 shell sand in company with Diplommatina, Georissa, Kaliella, 

 all little land shells living among rocks, and evidently washed 

 down to the sea. 



IV. SPECIES OF WESTERN SIBERIA, TRANS-CAUCASUS AND THE 

 EUROPEAN TERTIARY. 



Gastrocopta appeared in Europe in the middle Oligocene. 

 The subgenus Albinula is represented by the series of G. 

 quadriplicata, which in various mutations continued to the 

 Upper Pliocene (G. fossanensis, Piedmont). 



The subgenus Sinalbinula began with species of the G. 

 didymodonta series in the Upper Oligocene, became extinct in 

 Europe at the close of the Miocene, but still survives in the 

 recent Trans-Caucasian G. theeli. The series of G. nouletiana, 

 in several successive slight mutations, existed through the 

 Miocene. 



The fate of Gastrocopta in Europe was determined, we may 

 suppose, by the lowering of temperature which closed the 

 Pliocene ; but it should also be noted that the stock was appar- 



