410 Prof. T. R. Jones on the 



and a straight dorsal edge, with blunt angles. On each valve 

 two short spikes project from the ventral edge. This is cre- 

 nated within with small regular pits, making a neatly serrated 

 junction ; the pairs of spikes, opposite one to the other, close 

 against each other when the valves are shut. 



Seen sideways this fossil looks like a little halfmoon-shaped 

 equal-ended boat, standing on its convex edge, with two 

 pointed feet instead of a keel. 



From the Bh'zopJti/Uum-heds of Lau, where it seems to be 

 rare. 



3. Bursulella unicornis^ Jones. (PI. XXII. fig. 7.) 



Bursulella unicornis, Jones, Silur. Ostrac. Gothland, 1887, p. 7. 



Valve triangular, with its dorsal corners rounded and its 

 ventral border narrowing into a long subcylindrical spike. A 

 few specimens have been found in the shale of Frojel and 

 the Cephalopodan Limestone of Samsugn and Slite. 



Note. — My friend Professor Lindstrom has sent me for 

 examination several small Entomostraca which he obtained 

 lately from a red clay at Wisby, Gothland, belonging to the 

 red marl-shales at the base of titricklandinia-Ya&xXs, (equiva- 

 lent to the Upper Llandovery) in Gothland. Among them 

 there is a Beyrichia Klcedeni (with hypertrophied front lobe) , 

 PoJycope, Q^.^ Leperditia, small sp., Bairdiai^), Pontocypris 

 Maiou, P. Smithu, Bythocyprts, spp., Gythere subquadrata (?), 

 and some probably undescribed species. These specimens 

 are from the basement of the lowest known Silurian strata of 

 Gothland. 



Note. — Whilst this paper was in the press I received from 

 Herr J. Kiesow, of Dantzic, a paper on some BeyricMce 

 from Gothland, published in the Zeitschr. deutsch. geol. Ges. 

 Jahrg. 1888. 



EXPLANATION OF THE PLATES. 

 Plate XXI. 



[All the figures are maguitied 15 diameters.] 



Fig. 1. Kloedenia apiculata, uov. a, right valve; b, edge viewj c, end 

 view. 



Fig. 2. The same. Left valve. 



Fig. 3. The same. Left ^alve. 



Fig. 4. The same, a, left valve, with the antero-ventral lohe hyper- 

 trophied ; b, edge view ; f, end view. 



