Palceozoic Bivalved Entomostraca. 347 



TTiey have smooth convex valves, impressed with two short 

 vertical furrows on the dorsal region ; and in the type a 

 third smaller furrow defines a narrow serailune at the front 

 end of the valve. Two such small, vertical, parallel fur- 

 rows characterize the variety plicata. B. Wilckensiana 

 differs so much in general features from typical Beyrichice 

 that we think this purse-like form ought to be raised to 

 generic distinction as Klcedenia, a name we propose to use 

 in honour of Karl Friedrich von Kloden, who first noticed 

 the Beyrichice. 



The furrows in Klocdenia do not alter the contours of the 

 valves so much as the deeper and broader four sulci in B. 

 bussacensis, Jones (Proc. Geol, Assoc, Pal. Biv. Entom. 

 1869, p. 15, fig. 23), and we may add perhaps B. Forhesii^ 

 Jones {ihid. fig. 19). This or a similar arrangement of parts 

 may hold good according to the description (not accompanied 

 by a figure) in Billings's B. decora (Sil. Foss. Anticosti, 

 1866, p. 66). Another possible ally is B. persulcata^ Ulrich, 

 from the Hudson-River Group (Journ. Cincin. Soc. N. H. 

 vol. ii. 1879, p. 4, pi. vii. fig. 6). B. pennsylvanica, Jones 

 (Ann. & Mag. Nat. Hist. ser. 3, vol. ii. pp. 252, 253, pi. x. 

 figs. 15-18), also possesses four lobes or ridges in its adult 

 form*. B. nana, Brogger (Die silurischen Etagen 2. und 3. ira 

 Kristianiagebiet und auf Eker, 1882, p. 55, pi. xii. fig. 15), 

 is also one of the four-lobed Beyricliicc. These Beyrichice 

 having more than three transverse lobes on their valves may be 

 grouped as Plurijugatce. Our new species Beyrichia admixta 

 (see further on) is one of this group, and B. lacujiata, sp. nov., 

 is not far removed from it. 



1. Beyrichia tidtercidata (Kloden). 



Battus tiihercuJatus, Kloden (pars), 1834, Verstein. Mark Brandenburg, 



pp. 115-117, pi. i. figs. 21-23. 

 Beyrichia tubermlata, Boll, 1847, Palfeontogr. vol. i. p. 127, 1862, 



Archiv Vereins Freunde Naturg. Meklenburg, 16. Jahr. p. 119, pi. O, 



figs. la,b; var. = B. Kochii, Boll, I. c. p. 121, fig. 2 (? = var. nuda, 



Jones). 

 Beyrichia tuhercidata, Jones, 1855, Ann. & Mag. Nat. Hist. ser. 2, 



vol. xvi. p. 86, pi. V. figs. 4-9 b ; Proc. Geol. Assoc, Pal. Biv. Entom. 



1869, p. 12, figs. 12 a, b,c; Geol. Mag. dec. ii. vol. iii. 1881, p. 344, 



pi. _x. figs. 8, 9, 10. 

 Beyrichia tuberc-ulata, var. nuda, Jones, 1855, op, cit. figs. 10, 11, et var. 



antiqtiata, fig. 12. 

 Beyrichia tubercidata, Karsten, 1869, Beitrage zur Landeskunde d. 



* The frilled specimens of this species (fig. 15) were wrongly referred 

 to B. Maccoyiana (loc. cit.). 



