372 CARBONIFEROUS LAMELLIBRANCHIATA. 



Eurfooz, etage II. The latter specimen is only a little larger than that of the 

 series I have obtained from Thorpe Cloud. Notwithstanding the difference in 

 mere size of the English specimens, I have no hesitation in referring them to de 

 Koninck's species. With regard to the small size which this species exhibits at 

 Thorpe Cloud, it is interesting to note that two other species of the genus, 

 3. Onialianns and S. angiistatus, which occur with it in the same bed, are also 

 much dwarfed, being only half the size of specimens of the same species obtained 

 from the Isle of Man or Ireland ; a few other species from that locality also 

 exhibit this condition of dwarfing. 



Sanguinolites angulatns seems to form a link between this genus and 

 Mytilomorpha ; but judging from the character of the ornament, so unlike that 

 which obtains in Mytiloviorpha, and the presence of a radiating line bisecting the 

 dorsal slope, never present in the latter genus, it is correctly placed with Sanguino- 

 lites. It is unfortunate, however, that the adductor muscle-scars and the hinge 

 have not been observed ; for it is often impossible to separate accurately shells 

 of different genera which possess similar forms on external characters only. 

 This species resembles S. argutits in having a very sharp keel and a much- 

 hollowed dorsal slope ; but it is easily distinguished by its more transverse shape 

 and the absence of well-marked concentric ribs on the surface. 



Sanguinolites Omalianus, de Konincl; sp., 1842. Plate XL, figs. 17 — 24. 



Pholadomya Omaliana, de Koninck, 1842. Anim. Foss. Terr. Carb. Belg., p. 65, 



pi. V, fig. 4. 



— TEANSTEESA, de Ri/clcholt, 1847. Mel. paleoutoL, le partie, p. 159, 



pi. ix, figs. 18, 19. 



— Omaliana, Bronn, 1848. Nomencl. palaeoiitol., p. 964. 

 Lyonsia Omaliana, d' Orlirjny , 1850. Prodrome paleoutoL, vol. i, p. 128. 



? Panop^a geatida, de lii/ckholt, 1853. Melanges paleontol., 2uie partie, p. 30, 



pi. xi, figs. 5, 6. 

 Mtacites? Omaliana, Morris, 1854. Cat. Brit. Tosss., p. 213. 



— — Baili], 1875. l"'igures of Char. Brit. Fosg., vol. i, p. 115, 



pi. xxxix, fig. 9. 

 Alloeisma Omaliana, Bujshy, 1878. Thesaurus Devonico-Carboniferus, p. 295. 

 Panopjea geavida, Bigsbij, 1878. Ibid., p. 311. 



Cn^NOMYA Omaliana, de Koninck, 1885. Aun. Mus. Roy. Hist. Nat. Belgique, 



vol. xi, p. 6, pi. i, figs. 12—15. 

 Nou Sanguinolites Omalii, de Koninck, 1885. Ibid., p. 74, pi. xv, figs. 11, 12. 

 — Mtacites Omaliana, Etlieridge, 1888. Brit. Foss., pt. 1, Palaeozoic, p. 286. 



