CLTNOPTSTHA. 445 



Dtstactella, Walcott, 1885. Monogr. U.S. Geo). Surv., vol. viii, p. 172. 

 Ci.iNOPiSTiiA, Hall, 1885. Pal. New York, vol. v, pt. 1, Lamellib., pt. 2, p. liv. 



— de Koninck, 1885. Anu. Mus. Eoy. Hist. Nat. Belg., vol. xi, 



p. 123. 



— Fischer, 1887. Manuel de Conchyliologie, p. 1157. 



— Keyes, 1888. Proc. Acad. Nat. Sci. Philadelphia, p. 233. 



— Miller, 1889. North American Geol. and Palseontol., p. 472. 



— Meek and Worthen, 1800. Geol. Surv. Illinois, Pal, vol. viii, p. 122, 



pi. xix, fig. 3; and pi. xxi, fig. 2. 



— Keji/es, 1894. Missouri Geol. Surv., vol. v, Pal., pt. 2, p. 124, 



pi. xlvi, figs. 11 a, b. 

 Janeia (pars), Beusltausei), 1895. Abh. Kcinig. Preuss. Geol. Landesanstalt, n. F., 



Heft 17, Lamell. Rheinisch. Devon, p. 293. 



Generic Gharacters. — Shell oval, thin, f^ibbose, close all round, very inequi- 

 lateral. Anterior end large and expanded ; posterior end almost obsolete. 

 Umbones small, posterior, with a boss (? ligament) behind them. Under surface 

 of umbo excavated for the ligament. Hinge edentulous. Pallial line entire. 

 Surface ornamented with fine concentric lines, almost smooth, with fine radiating 

 striae in some species. 



Observations. — The genus GUiiopistha was erected by Meek and Worthen for a 

 shell from the Coal-measures of Illinois, which had a certain affinity to Solenomya ; 

 but, as they point out, did not possess the ridge passing downwards and back- 

 wards from the beaks, and did not gape at either end. In addition, the shells of 

 this genus are not transverse like Solenomya, but are ovate or obliquely sub- 

 circular. Hall pointed out that certain shells referred to Di/stacteUa should, on 

 grounds of priority, be now placed with Glinopistha. Miller enumerated seven 

 species from Devonian and Carboniferous beds of America ; and de Koninck has 

 described three species from the Carboniferous beds of Tournai, Belgium — G. 

 ahbreviata, C. lata, and G. parviila, — but I strongly suspect that the first two are 

 really only varieties of the same species. I am fortunately able to figure and 

 describe G. ahbreviata, de Ryckholt, and G. parvula, de Koninck, from British beds. 

 Both species occur in the Fourlaws Limestone at the Coomb, a little south of the 

 village of Hedesdale, Northumberland, an horizon supposed by the Geological 

 Survey to be the homotaxial equivalent of the lower part of the Yoredale series 

 of Wensleydale. The rich fauna of the Limestone at the Coomb Quarry has been 

 brought to light by the splendid work of Mr. J. Dunn, of Redesdale, and he has 

 obtained at this place a very large number of the species which have been collected 

 at Lowick by the Rev. E. Jenkiuson, who unfortunately did not record from which 

 of the several beds of Limestone at Lowick he obtained the fossils. 



A species of the genus Glinopistha was recognised as a new form by de Ryck- 

 holt {op. cit.), who referred it to Solemya as 8. ahbreviata as long ago as 1853, 



