298 MES, JAXE LOXGSTAFP OX SOME NEW [Scpt, I912, 



of the band, together with the general shape of the shell, is quite 

 sufficiently distinctive to indicate the advisability of separating 

 these forms horn Pleurotomaria sensu stricto. They probably belong 

 to the Eaphistomidae as defined by Ulrich,^ and constitute a genus 

 intermediate between Bapliistomina Ulrich and Euomplialopterus 

 Eoemer. Ulrich thinks the former genus the more ancient, and 

 suggests that Euomjjlialo;pterus has been derived from it ; if this be 

 the case, we may perhaps further regard Tropidostroplia as another 

 derivative. 



Tkopidostbopha gkiffithi (M'Coy). (PI. XXYII, figs. 1-4.) 



Fleurotomaria griffithii F. M'Coj-, 1844, 'Syn. Char. Carb. Limest. Foss. Irel.' 

 pp. 40-41 & pi. vi, figs. 1-1 h (uon Fl. griffithii L. G. de Kouinck, 185] : 

 ' Descr. Aiiim. Foss. Terr. Carb. Belg.' Suppl. p. 695 & pi. Iviii, fig. 10). 



Fleurotomaria griffithii J. Morris, 1854, ' Catal. Brit. Foss.' p. 273. 



Fleurotomaria griffithii (pars) F. M'Coy, 1855, '' Brit. Pal. Foss.' pp. 528-29. 



Fleurotomaria griffithii E. GriflBth, 1860, Jouru. Geol. Soc. Dublin, vol. ix, 

 pp. 90 & 125. 



Fleurotomaria griffitJiii J. J. Bigsby, 1878, 'Thes. Dev.-Carb.' p. 331. 



Mourlonia griffithi L. G. de Kouinck, 1883, ' Faune du Calc. Carb. de la 

 Belgique ' pt. iv, Ann. Mus. Eoy. Hist. Xat. Belg. vol. viii, p. 78 & pi. xxiii, 

 figs. 29-30. 



Fleurotomaria griffithii R. Etberidge, 1888, ' Foss. of Brit. Is.' vol. i. Pal. 

 p. 305. 



Diagnosis. — Shell very large. Whorls about six, moderately 

 convex above, slightly concave on each side of the band. Band 

 situated near the middle of the body- whorl, and on the lower fourth 

 of the penultimate whorl, composed of a sharp prominent keel 

 overlying a slightly-concave rectangular band, which is limited 

 on each side by a strong thread, with a much finer thread down the 

 middle and crossed by fine crescentic threads. Test thin. Lines 

 of growth coarse, irregular, broken and sometimes bifurcating, 

 sweeping obliquely backwards to the edge of the keel above, 

 forwards at first below, and then passing almost vertically into the 

 umbilicus. Base convex, with a subangularity or broad rounded 

 ridge surrounding the umbilicus. Aperture wider below than 

 above, sharply angular at the periphery where the keel occurs. 

 Inner lip unknown. Umbilicus wide. 



Remarks and resemblances. — !\I'Coy ('Syn. Char. Carb. 

 Limest. Foss. Irel.' p. 40) describes this species as having 'a single, 

 very prominent, square keel,' evidently founding his description 

 upon a specimen in which the band was imperfectly preserved. 

 That such was the case I have been able to ascertain through 

 the kindness of Dr. Scharff, who sent me a good model and several 

 photographs of the holotype. He also lent me specimens which 

 are conspecific, and exhibit the surface and band in better condition. 

 Prof. Hughes, at the same time, was most obliging in lending me 

 the examples in the Sedgwick Museum referred to by M'Coy in 

 ' Brit. Pal. Foss.' pp. 528-29. I discovered that he was mistaken 



^ Final Kep. Greol. & Nat. Hist. Surv. Minnesota, vol. iii, pt. ii (1897) 

 p. 930. 



