1901.] NATURAL SCIENCES OF PHILADELPHIA. 471 



die Baleo-Clausilien die direkten nachkommen des Prototyps der 

 Europiiischen Clausilien sind." 4 



The conclusion that Eeinia stands in close relationship with 

 Phcedusa, and has nothing to do with Balea, was forced upon 

 me by the study of a series of Japanese species, before I knew 

 that von Mollendorff, nearly twenty years ago, had been led to 

 the same result by the structure of a Chinese form. Only in one 

 point of view the data before me seem to modify the ideas of the 

 Oerman savant: the Japanese series establishes such a connection 

 between Eeinia and Euphcedusa that the descent of the former 

 from the latter is strongly indicated. Eeinia is not a primitive 

 P/icedusa, but a degenerate one. I regard Eeinia variegata as the 

 secondarily simplified end of a series leading from typically 

 Euphsedusoid ancestors, just as Balea perversa is a secondarily sim- 

 plified, and not a primitive, Clausilia. The east Asiatic series 

 leads from forms with many whorls, well-developed clausilium, 

 lamelke and folds, and continuous peristome, to those with few 

 whorls, no clausilium, the lamellae and plicae reduced and in part 

 lost, and the peristome adnate above and finally interrupted. 

 Bottger has demonstrated that the older tertiary Clausiliidaz of 

 Europe had a narrow clausilium and the superior lamella was 

 continuous with the spiral lamella; the widening of the clausilium 

 and separation of the superior and spiral lamellae being modern 

 characters. Now Eeinia and its nearest allies have the spiral 

 and superior lamellae interrupted, and the clausilium when devel- 

 oped is of the very broad type. These considerations seem to 

 render the hypothesis that Eeinia is a primitive Phcedusa quite 

 inadmissible. 



The chief characters of Eeinia and the Euphsedusoid forms 

 leading toward it, are stated in the following table : 



4 L, c., p. 265. 



