alceozoic Bi valued Entomostraca. 65 



7. Beyrichia stn'cti.'iulcafa, Sandbergcr, MS., sp. n. 

 (PI. Vll. li-. 11.) 



This oblong Beyrichia i.s allied to B. Kloedeni by its well- 

 dcvclopcd three ridges, which, as in somewhat similar forms, 

 stand out nearly equ.d, equidistant, and almost ])arallel. It 

 issuflicientlj distinct, however, to bear Prof, von Sandbcrger's 

 proposed name of sirictisulcata. 



It occurs, together with Atrypa and Primitia sacculus, in 

 the dark grey, fine-grained sandstone at Offdillen above men- 

 tioned, and is fairly abundant. 



8. Bollia varians^ Sandberger, MS., sp. n. 

 (PI. Yll. figs. 8-10.) 



This characteristic Bollia is longer and more nearly oblong 

 than the majority of the published figures of this genus. The 

 form most closely allied is Bollia ungula (Claypole, MS.), 

 Jones, Amer. Geologist, December 1889, p. 338, tigs. 10-13. 

 The chief diflerenees are : — (1) in the Nassau specimens here 

 figured the inner, semicircular, or horse-shoe ridge is not so 

 thick and is more open ; (2) the dorsal end of one half of the 

 horse-shoe forms a knob in tigs. 8 and 10 ; (3) the second ridge 

 is larger and more distinct than in B. ungula, though (as 

 in the Pennsylvanian examples here referred to) its ventral 

 portion is sometimes evanescent. 



B. unguloidea and subaquata, Ulrich, and B. semilunata^ 

 Jones, are shorter, rounder, and otherwise different ; so also 

 is B. Jlindei, Jones, in which both tops of the horse-shoe 

 ridge are contracted to knobs ; and this is a feature with one 

 of the tops in both unguloidea and subcequata. 



The SjK'citie characters of these German specimens (figs. 8- 

 10) are well marked, and the unstable features of the curveil 

 ridges support Prof, von Saudberger's suggested name of 

 varians for this species, which is rather rare in the Lower 

 Devonian of OttUillen, Dilleuburg, Nassau. 



A7in. cO Mag. X. Hint. Ser. G. Vol. xv 5 



