SANGUINOLITES COSTELLATUS. 377 



may become somewhat ribbed concentrically. The dorsal slope is crossed by a 

 single radiating line, which, however, is not always present. Shell thin. 

 Dimensions. — Fig. XLT, PI. 7, measures — 



Antero-posteriorly . . . .61 mm. 



Dorso-ventrally . . . .29 mm. 



Gibbosity of valve . . . .15 mm. 



Localities. — Ireland : the Carboniferous Limestone of Ballygarrane and 

 Doohybeg, co. Limerick. 



Observations. — This species was founded by de Kouinck upon a single valve, 

 obtained from the Limestone of Waulsort, Belgium, by M. Ed. Dupont. It is, 

 however, such a peculiarly shaped shell that there is little or no difficulty in 

 recognising the species. The narrow anterior and expanded posterior end, the 

 oblique rounded gibbosity, and the fineness of the external markings are a series 

 of characteristics which may be relied upon as features diagnostic of the species. 

 I have, unfortunately, not been able to obtain any particulars of the interior, as all 

 the Irish examples to which I have had access for study possess the test. 



Sanguinolites Walciodorensis was referred to the genus Ghgenomya by de 

 Koninck; but, for reasons referred to above, I cannot distinguish any characters 

 sufficient to separate the shells, which were described by de Koninck as belonging 

 to this genus, from Sanguinolites as amended by him. The specimens, figs. 5 — 7, 

 PI. XLI, are in the collection of the Geological Survey of Ireland, in the Museum 

 of Science and Art, Dublin. I found them on tablets bearing the name Myacites 

 tumidus, Phillips, sp. 



Sanguinolites costellatus, M'Goy, sp., 1851. Plate XLI, figs. 8 — 10. 



Non Sanguinolites costkllatus, M'Coi/, 1844. Synopsis Carb. Foss. Ireland, p. 48, 



pi. viii, fig. 5. 

 Leptodomits costellatus, M'Coy, 1851. Ann. Mng. Nat. Hist., ser. 2, vol. vii, 



p. 175. 



— — Morris, 1854. Cat. Brit. Foss., 2ud edit., p. 206. 



— — M'Coy, 1855. Brit. Pal. Foss., p. 508, pi. 3r, fig. 5. 



— — Young and Armstrong, 1871. Trans. Geol. Soe. 



Glasgow, vol. iii. Supplement, p. 52. 



— — Young, Armstrong, and Robertson, 1876. Cat. West. 



Scottish Foss., p. 54. 



— — Bigshy, 1877. Thesaurus Devonico-Carboniferus, 



p. 307. 



— — Etheridge, 1888. Brit. Foss., pt. 1, Palaeozoie, p. 284. 



Specific Characters. — Shell transversely ovate, exceedingly gibbose, very in- 



49 



