4^^^ CARBONIFEROUS LAMELLTBRANCHTATA. 



but up to the present time no other European writer, with the exception of 

 cle Koninck, has recorded the presence of tlie genus. It would, therefore, appear 

 to be very rare, and to have a very limited distribution. 



The type of the genus, C. radiata, is the only species recorded from American 

 Carboniferous rocks; but apparently the genus is better represented in tlie 

 Devonian strata of North America. I cannot find any species described in works 

 on European Devonian Laraellibranchs. 



Beushausen (op. clt.) considers GUnop'istlia to be identical with the SoJi'noDiya 

 of the Carboniferous rocks, and employs King's name, Janeia, for them ; but I 

 tliink it batter to retain Meek and Worthen's genus for the less transverse, oval, 

 or suborbicular forms, which are closed all round, and have given my reasons in 

 my remarks on Soleiiomya, p. 43G, for not adopting King's genus Janeia. 



Clinopistha abbreviata, ih Biicl-lioU, sp., 1853. PI. L, fig. 17. 



SoLEMTA ABBREVIATA, de Syckholt, 1853. Melanges palcontol., pt. 2, p. 53, 



pi. xvi, figs. 18, 19. 

 — — Bifjshy, 1878. Thesaurus Devonico-Carboniferus, p. 313. 



Ci.iNoiMSTiiA ABBEEViATA, de Koninclc, ]885. Ann. Mus. Eoy. Hi^t. Nat. Bt-lg., 

 vol. xi, p. 123, pi. xiv, figs. 48 — 50 ; pi. xxiii, figs. 15 — 19. 

 — LATA, de Koninck, 1885. Ibid., p. 124, pi. xii, figs. 5, 6. 



Specific Characters. — Shell of only moderate size, obliquely suboval, gibbose, 

 very inequilateral, the posterior end being almost obsolete and much narrower 

 from above downvv^ards than the anterior extremity. The anterior end comprises 

 the greater part of the valve, and is swollen and expanded; its border commences 

 above at a more or less well-marked obtuse angle with the hinge-line, from which 

 it descends downwards and a little forwards, and soon becomes markedly curved, 

 forming the segment of a fairly large circle, and passes without a break into the 

 lower border, which is convex, but much less so than the anterior margin. The 

 posterior margin is regularly rounded, and the segment of a much smaller circle 

 than the anterior end. The superior margin is long and almost straight in front 

 of the umbones, but short and depressed posterior to them. The umbones are 

 small, directed backwards, hollowed posteriorly by the escutcheon, slightly 

 elevated and tumid, and placed very far backwards. The valves are regularly 

 but obliquely convex, the greatest convexity at about the centre of the valve. 

 Along the upper border, in front of the umbo, is a long obscure groove. Behind 

 the umbones is a boss, which occupies the upper part of the escutcheon possibly 

 representing the segment. 



Interior. — The details of the interior are unknown ; but the hinge is edentu- 



