1901.] NATURAL SCIENCES OF PHILADELPHIA. 473 



The interrelations of the above species are further illustrated in 

 the following diagram, the median portion of which shows the 

 probable phylogeny of the forms under consideration : 



r 



Aperture 

 wide 

 above. 



Aperture 

 piriform. 



Peristome 

 incomplete 



Peristome 

 j complete, 

 1^ no sup. lam. 



f No superior 



I lamella. 



I 



Superior la- 

 mella de- 

 L veloped. 



variegata 

 nesiotica 



No clausilium or 

 palatal plicae. 



[ Eastlakeana — 



— euholostoma 



monelas7nus 

 -Hungerfordian a 



normal 



Eupfuedusa 



Clausilium and 

 palatal plicre de- 

 veloped. 



It will be seen from the table and diagram that no sharp line 

 can be drawn between Reiiila and Euphccdasa. The number of 

 whorls varies, by easy stages; the form of the aperture is not cor- 

 related with other characters; and upon the whole, it is obvious 

 that we have to deal with forms in various stages of change and ot 

 degeneration of the closing- apparatus, from an Euphaidusoid ances- 

 tor. In fact, it is not quite certain that they had a single common 

 progenitor; they may be descendants from three species of Euphce- 

 dusa ; but however this may be, it is obvious that the original 

 stock, whether one or three, belonged to the aeulus group of 

 Euphcediisa; and some apparently trivial features of the whole 

 series, such as the peculiar coloration, give me reason to believe 

 that the phylogeny indicated above is not far wrong. 



Clausilia (Reinia) variegata (A. Ad.). PL XXV, figs. 11, 12. 



Balea variegata A. Adams, Ann. and Mag. Nat. Hist. (ser. 4), I, p. 

 469 (1868); Kobelt, Fauna Jap., p. 63, PI. 9, fig. 20 (1879) ; Mai- 

 tens, Sitzungsber. Ges. Naturforsch. Freunde zu Berlin, 1877, p. 105. 



The shell is sinistral, rimate, thin, tapering-pupiform, the last 

 whorl widest; streaked xvlth opaque buff on an olivaceous or 

 brownish corneous ground, and more or less marked with spiral 

 lines of the darker color. The surface is irregular striatulate, the 

 last half of the last whorl being striate. Whorls 6, convex and 

 regularly increasing. The aperture is broadly ovate, with white. 



