GASTROCOPTA, EUROPE. 113 



ently rather inflexible, and competitors of the same family 

 were more numerous, perhaps, than in any other part of the 

 world. 



The first European Gastrocoptas were described by Dupuy 

 in 1850. Shortly after, Al. Braun described the leading Ger- 

 man species, in Walchner's Geognosie, 2d edition. In the 

 copy of this work at hand, as well as in two others on which 

 bibliographic data are available, there are but 1120 pages; 

 beginning Braun 's contribution, but not containing the Pupae ; 

 so that I have copied references from Sandberger. The date 

 of the later pages is uncertain. Sandberger, in Die Con- 

 ehylien des Mainzer Tertiarbeckens, 1863, and Die Land- und 

 Siisswasser-Conchylien der Vorwelt, 1870-1875, and especially 

 Dr. Oskar Boettgei 4 in his admirable paper, Die Entwickelung 

 der Pupa-Arten des Mittelrheingebietes in Zeit und Raum, in 

 Jahrb. Nassauischen Vereins Naturkunde, 1889, are the chief 

 authorities ; but references to numerous other authors will be 

 found below. Perhaps there are other described species; the 

 plan of this work does not include a thorough review of 

 palaeontological literature. Really adequate illustrations of 

 European Tertiary species are still wanting. 



Dr. O. Boettger classified the European Tertiary Gastrocop- 

 tas (Leucochilus) in three groups, noted below. Of these 

 groups, that of quadriplicata was said by Sandberger to be 

 related to the recent American G. contracta. Boettger consid- 

 ered quadriplicata an ancestor of contracta. I have figured a 

 French Pliocene species of this group, G. dupuyi (pi. 22, figs. 

 1, 2, 4) to show the resemblance. It will be noted that the 

 angular and parietal lamellae are wholly concrescent, and the 

 parietal turns towards the periphery at its inner end; also 

 it has a direct inward spur (pi. 22, figs. 2, 4), some trace of 

 which can be seen in the recent American G. armifera also. 

 The columellar lamella turns down at the inner end (fig. 4), 

 and the palatal plicae stand upon a callous ridge. These are 

 characters of both the armifera and contracta groups of 

 AlUnula, which indicate, at least, that the American and 

 European species are of common immediate ancestry, though 

 it appears to me that the European stock is a little too special- 



