Palceozoic Bivalved Entomostraca. 403 



In fig. 14 (a right valve) the prickles of the surface are 

 more numerous ; the hinder lobe shows no sulcation, as in the 

 var. antiquata (Ann. & Mag. Nat. Hist. August 1855, p. 87, 

 pi. V. fig. 12), and the upper moiety of the front valve is 

 reduced to a narrow, curved, rugose ridge ; the hind and 

 front margins are denticulate. 



7***. BeyricMa tiiberculata, var. foliosa, nov. 

 (PI. XXL figs. 15-17.) 



In figs. 15 and 16 the superficial isolated prickles are 

 exaggerated into somewhat concentric rows of large and 

 small spines, directed backwards on the posterior and for- 

 wards on the anterior part of the valve, and less regularly- 

 arranged tubercles occupy the inner slope of the hinder or 

 gigot-lobe. The middle lobe is distinct, as in all the other 

 specimens of these Beyrichice ; but the hinder lobe is no 

 longer rounded and divided crosswise, and the front lobe is 

 also obsolete or shapeless and overgrown with tubercles. 



Fig. 17 has a still more extreme variation in its concentric 

 overlapping growths of leaf-like, coarsely denticulated expan- 

 sions over the hinder lobe, which retains the dorsal projec- 

 tion, seen also in figs. 12-15. The middle lobe is distinct 

 and smooth ; the front lobe is smooth and low above, but 

 prominent and partially tuberculate in its lower moiety. 



The originals of figs. 12-17 are well-preserved white speci- 

 mens from the Uppermost Silurian strata of Slite, Gothland. 



YI. Lepeeditia, Rouault, 1851. 



(Ann. & Mag. Nat. Hist. ser. 2, vol. xvii. 1856, p. 84, and ser, 5, 

 vol. viii. 1881, p. 333 &c. ; Proc. Geol. Assoc, vol. ix. 1886, p. 503.) 



1. Lepej'ditia grandis, Schrenck. 

 (PI. XXII. figs. 11a, lU.) 



(Silur. Ostrac. Gothland, 1887, p. 3.) 



This Lepe^'ditia is evidently a small individual of L. gran- 

 dis, as described and figured by Fr. Schmidt in the Mem. 

 Acad. Imp. Sci. St.-Pdtersb. sdr. 7, vol xxi. 1873, p. 10, 

 figs. 1-6 a. According to him it is the same as F. Homer's 

 L. gigantea. 



This right valve, figured in the drawings sent from Stock- 

 holm, shows distinctly at its ventral margin the two minute 



