412 CARBONIFEROUS LAMELLIBRANCHIATA. 



crushed; but, on the other hand, specimens showing the interior as well as the 

 surface-markings can be obtained by carefully splitting the shale. 



The generic characters of this species are quite certain ; the ridge posterior to 

 the anterior adductor scar, and the entire paUial line, separating it from Allorisma, 

 and the presence of an escutcheon and hmule from Edmondia, I am not, however, 

 able to refer the shell to any hitherto described species, nor has it any close 

 resemblance to any other species of the genus. 



Genus — Solenopsis, M'Goy, 1844. 



SoLEN (pars), Goldftiss, 1832. In Handb. Geognosie (De la Becbe ; translation), 



p. 531. 



— — 1840. Petreiacta G-erm., vol. ii, p. 270. 



— Portloch, 1843. Eej)!. Geol. Londonderry, p. 441. 

 Solenopsis, MCoy, 1844. Synops^. Carb. Foss. Ireland, p. 47. 



.? SOLENELLA, de Eyckholt, 1847. Mel. Paleontol., 1st part, pi. xi, fig. 17. 

 CyPEiCAKDiA (pats), d'Orhigny, 1850. Prodrome de Paleontol., pt. i, p. 75. 

 Ltonsia (pars), d'Orhigny, 1850. Ibid., p. 129. 

 SoLEN ? Morris, 1854. Cat. Brit. Toss., 2nd edit., p. 224. 



— Swallow, 1858. Trans. St. Louis Acad. Sci., vol. i, p. 190. 



— Winchell, 1862. Proc. Acad. Nat. Sci. Pbil., p. 422. 

 Solenopsis, Baihj, 1862. Expl. Sbeet 127, Geol. Surv. Ireland, p. 9. 

 CLiDOPnoEUS, Geinitz, 1866. Carb. ii. Dyas in Nebraska, p. 25. 

 Solenopsis, Hayden, 1872. U.S. Geol. Surv. Nebraska, p. 223. 



— (pars), Bigshy, 1877. Thesaurus Devouico-Carboniferus, p. 313. 



— de Koninck, 1885. Ann. Mas. Eoy. Hist. Nat. Beige, vol. xi, p. 88. 



— Fischer, 1887. Man. de Conchy liologie, p. 1112. 



— Etheridge, 1888. Biit. Foss., pt. 1, PaljBozoic, p. 291. 



— 31iller, 1889. N. Amer. Geol. and Pakeontol., p. 512. 



— Beiishausen, 1895. Abh. Kouigl. Preuss. Geol. Laudesanstalt, 



Heft 17, p. 210. 



Generic Characters. — Shell small, narrow, very inequilateral ; posterior end 

 narrowed and produced, compressed. Umbones small, inconspicuous, and placed 

 very far forwards, with an obscure swelling passing from the umbones to the 

 postero-inferior angle. 



Interior. — Anterior adductor muscle-scar round or ovate, deep, with a small 

 accessory scar above it. Posterior adductor scar very flat, obliquely oval. Mantle- 

 line entire. Ligament external. 



Exterior. — The surface is covered with fine concentric lines and strige of 

 growth. 



Observations. — This genus was established by M'Coy to receive a single 

 species, S. minor, but the genus has been adopted by both European and 

 American palaeontologists. Beushausen has given a longer and more complete 



