190 On the Paheozoic Bivalved Entomostraca. 



more oval and less rectangular in figure than in perhaps more 

 typical examples. The ridges vary in strength and sharp- 

 ness, being sometimes very high and wall-like ; the central 

 concentric ridge, or escutcheon, as we have termed it, is 

 occasionally imperfect ventrally. There are also other slight 

 variations, as in all the Kirkbyce ; but, on the whole, this is a 

 well-marked and characteristic species. It is of interest also 

 on account of its having been discovered by the Rev. David 

 Ure, of Rutherglen, in the Carboniferous-Limestone series of 

 Western Scotland, so far back as 1793 or before. Specimens 

 of it, along with other Microzoa, were sent by him to his 

 friend Dr. John Hunter, in London, who placed them in his 

 Museum, now the Hunterian Museum, Royal College of 

 Surgeons, where they were noticed by one of us more than 

 sixty years afterwards. 



Localities. — England. Carboniferous-Limestone series: Dun 

 Quarry near Lowick, Skellygate (Ridsdale), Scremerston, in 

 Northumberland ; Holker Park, Lancashire. 



Scotland. Carboniferous Limestone (Lower) : Brockley, 

 High Blantyre, Head of Mouse Water, Capelrig Quarry, 

 Brankumhall Quarry, and elsewhere in Lanarkshire ; Craig- 

 englen, Stirlingshire ; Murray field Old Pit, Whitebaulks 

 Quarry, Linlithgowshire ; Burlage Quarry, East Lothian ; 

 Darcy Limestone Quarry, Edinburghshire ; Inverteil Quarry, 

 Coast near Abden and Seafield Tower, Wilkieston Quarry, 

 Coast east of St. Monans, Sunnybank Quarry, Glenniston 

 Quarry, in Fifeshire. Carboniferous Limestone (Upper) : 

 Robroystone. 



Besides the foregoing species there are some other forms 

 which additional material and further study may show to 

 belong to Kirkbya. Certain of these forms (from the Lower 

 Carboniferous beds) are rather perplexing in their double 

 and almost equal relationship to Beyrichia and Kirkbya. To 

 these we shall recur at some future opportunity. 



Note. — In the Zeitschrift deutsch. geol. Gesellsch. 1867, 

 Dr. R. Richter has figured and described Kirkbya Richteriana 

 (p. 224, pi. v. figs. 1-3) and K. collaris, sp. nov. (p. 225, 

 pi. v. figs. 5, 6), from the Zechstein of the neighbourhood of 

 Saalfeld. 



EXPLANATION OF PLATE III. 



(The figures are all magnified 25 diameters.) 



Fig. 1 . Kirkbya permiana, Jones. Left valve. Carlops. 

 Fig. 2. Kirkbya umbonata ( D'Eichwald), var. radiata. Eight valve. 

 Fig. 3. Kirkbya oblonga, Jones and Khkbv. Eight valve. Kinneil 

 Mill'. 



