66 On the Palceozoic Bivalved Entomostraca. 



9. Drepanella serotinn, Sandberger, MS., sp. n. 

 (PL VIL %. 12.) . 



For an account of the genus Drepanella see UMch's 

 memoirs (Journ. Cincinn. Soc. N. H. vol. xiii. 1890, p. 117, 

 and Geol. Surv. Minnes., Last Report, vol. iii. 1894, p. 670). 

 The present form may look upon D. ampla, Ulrich (1890, 

 p. 120, pi. viii. fig. 2), as a near allj, although the sickle- 

 shaped ridge on the ventral region is shortened to a straight 

 thick ridge, and the two pointed knobs above are represented 

 by two unequal roundish tubercles. Hence the species is 

 different for the German form ; and von Sandberger's name 

 serotina may well be adopted for this Zate, if not last^ represen- 

 tative of the genus. 



Drepanella seems to have been an outcome of Bollia rather 

 than of Beyrichia ; but its evolution is not a matter for dis- 

 cussion at present. 



From the Lower Devonian of OflfdlUen, Dillenburg, Nassau. 



10. Strepula? annulata, Sandberger, MS , sp. n. 

 (PI. Vli. fig. IS.) 



This very curious little unique form was found on a large 

 block of the OrthocerasSchieiev (Lower Devonian) at Off- 

 dillen ; and fig. 13 is copied from the drawing supplied by 

 Prof. von. Sandberger. The outer ridges and central eleva- 

 tions are not quite comparable with the features of any known 

 Strepula, but to that genus the present example seems to have 

 the nearest affinity. 



EXPLANATION OF PLATE VII. 



[The figures 1-7 are mag-nitied 20 diameters, excepting figs. 4 c and 5 6, 

 which are xGO. Figs. 8-13 x30 diam.] 



Fiff. 1. Prhnitia nitida (F. Roemer). a, left valve ; I 



6, edge view. ( au tt 



Fig. 2. The same, an older individual, a, left valve ; ' ^^^enau, Marz. 

 b, edge view. ) 



Fi(j. 3. Prmtitia Itevvjata, sp. u. a, left valve ; b, edge 

 view. 



Fi(]. 4. Aparchites reticulatus, sp. n. a, right valve ; ^ ^^'^i^^'^- 

 6, edge view ; c, portion of ornament. 



