On Some Carboniferous Entomostraca from Nova Scotia. 357 



members of the species, by their narrower anterior extremity, and 

 their pronounced posterior obliquity. These specimens are illus- 

 trated in Fig. 3. They are small, being only about -2-0- inch, 

 or 1-4: millimetre long, and 1 mm. in height, of which size they 

 occur in European strata, though they are as often found larger, even 

 up to double the length. 



This species has been described and figured by us from Bavarian 

 specimens (supplied to us by Dr. Giimbel) and Russian material 

 (from the late Dr. von Eichwald), in the Annals and Magazine of 

 Natural History, ser. 3, vol. xv. 1865, p. 406. 



2. — Lepekditia Okeni (Miinster), var. Scotohurdigalensis (Hibbert). 



Zeperditia Okmi, Acadian Geology, 1868, p. 256, fig. 7^l>- L. Scotohurdigalensis 

 (Hibbert), Jones, Proceed. Berwicksh. Nat. Club, vol. iv. 1884, p. 321. 



Along with the just noticed specimens are other Leperditice, much 

 less oblique, with extremities of about equal width (or height). 

 These, in some instances considerably lai'ger, are represented by 

 Figs. 1 and 2 ; and we have no hesitation in identifying them with 

 the form hitherto considered a variety of L. Okeni, under Hibbert's 

 name of Scotohurdigalensis. Dr. Hibbert described and figured it, 

 in his well-known paper on the Burdiehouse limestone, as a Ci/pris. 

 In 1866 we had an opportunity of examining Dr. Hibbert's speci- 

 mens, as well as others collected at Burdiehouse, by several friends, 

 the result of which satisfied us that the Entomostracan in question 

 is a Leper ditia nearly allied to L. Okeni : Ann. Nat. Hist. ser. 3, 

 vol. xviii. p. 34. 



L. Okeni is a species with several near relations, for the present 

 looked upon as varieties. Whether some of them, and Scotohurdi- 

 galensis among the number, may not ultimately have to be separated 

 from it, as distinct species, is an open question ; for a careful re- 

 examination of these Leperditice has long been a matter to be 

 desired, and it is one now that we hope soon to overtake. 



At Burdiehouse, both in the limestone and in the shale associated 

 with it, L. Okeni, var. Scotohurdigalensis, is extremely abundant. So 

 much so that its carapace-valves (often more or less crushed) appear 

 to compose or build up the rock in which they occur. It is just as 

 plentiful in other beds, at many places in Scotland, more especially 

 in Fife ; but always in the Calciferous Sandstone (Tuedian) or 

 Lower-Carboniferous portion of the series. 



It is of especial interest to meet with so old a friend, as it were, 

 so abundantly, and under so robust a habit — for we have never 

 seen larger examples of it in Scotland — in Carboniferous rocks on 

 the American side of the Atlantic, and occupying about the same 

 stratigraphical position as in Britain. 



3. — Leperditia Okeni (Miinst.), var. acuta. Plate XII. Figs. 4a, h. 



L. Okeni, var. acuta, J. and K., Ann. M. N. Hist. ser. 3, 1865, vol. xv. p. 406. 

 Cythere? Dawson, Acadian Geology, 1868, p. 206, fig. 48c? 



Fig. 4a represents the right valve of a comparatively small, but 

 relatively long Leperditia, that has the anterior half much narrower, 



