Lower- Carboniferous Entomostraca. By T. R. Jones. 323 



down in the M,-L. group. Often the valves are destitute of this 

 fringe ; but that is not to be wondered at, as in many other 

 instances of broad-margined palaeozoic Beyrichice (Carboniferous 

 and Silurian), sometimes with a radiated ledge, the thin edge has 

 been broken away and lost. 



Forms closely allied to B. crinita are known in the Calciferous- 

 sandstone series at BiUowness, Fifeshire, and in the Carboni- 

 ferous shales at Cultra in Ireland. The fringe, however, differs, 

 chiefly in being more delicate, and the sidci and lobes of the 

 surface have differences in the several forms. 



8. KlRKBYA SPIRALIS, J. & K., MS. 



PI. II., figs. 12 and 13. 



Valves subovate, 1 millim. long, with a height of more than 

 half the length ; probably thin, bordered with a delicate raised 

 rim, which sends off a branch from its dorsal portion into the 

 central area, and this, curving along the broader third of the 

 valve, concentrically with its edge, turns towards the ventral 

 margin, skirting it in good specimens ; and, returning over the 

 posterior third, encloses an independent, medial, longitudinal 

 somewhat sinuous ridge. The characteristic medial pit or 

 depression is also present. These features are modified in the 

 crushed specimens before us (especially in fig. 12). This species 

 is rare in "C," from Tweedmouth, Lower M.-L. group. It occurs 

 in the Calciferous-sandstone, Fife, where it was discovered by 

 Mr J. W. Kirkby in 1878 ; and we have a similar form from 

 Soignies, Belguim. It is allied to X. cosfata (M'Coy), in which 

 the ridges are stronger, more numerous, and more regularly 

 disposed; also to JT. pUcata, J. & K., MS., and another ridged 

 Eirkbya, aU from Lower-Carboniferous strata. 



9. Cytherella Tatei, sp. nov. 

 PI. II., figs, la, lb, Ic. 



Valves small (-75 millim. long), smooth, white, thick, close- 

 fitting, convex, oblong-ovate ; breadth (height) equal to about 

 two-thirds of the length, the greatest convexity rather more 

 central than usual in the genus. The relative shortness, breadth, 

 (height), and convexity of this species serve as distinctions. 



A few specimens occur in a shale (" M," see page 315) from 

 the Lower Mountain-limestone group at Lamberton, containing 

 Spirifer, &c. 



Two obscure Cytherellce (?), of similar broadly ovate shape, 

 occur in the piece of fossHiferous rock " H," from the Middle 



