BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 18. AFD. IV. N:0 1. 49 



ill the hemispherieal. But this question I must leave to be 

 decided by tliose who ha ve at tlieir disposal a greater niimber 

 of specimens. 



Discoidea cylindrica Ag., forma elatior, the peristome from the insida. 



In the Galerites Albogalerus Leske the auricular system, 

 as forestalled already by Desmoulins,^ is constriicted iipon the 

 same principle as in the Discoidea, but modified in a peculiar 

 way.- The auricular branches of each ambulacrum, well defined 

 by distinct sutures, are slightly more separating than in the 

 lower form of Discoidea cylindrica, proportionally longer, and 

 nearly as slender as in the elevated form, and, like eitber of 

 theni, provided on the ambulacral side of the top with a mi- 

 nute and glossy projection. The broad interradial wall, which 

 equals the auricle in height, bas a middle convexity between 

 two ratber deep impressions. Thus far the conformity with 



' Etudes, I, p. 25, 189. 



^ See woodcut on the next page. 



