230 MISS J. DONALD ON THE GENUS [May 1 895, 



Murchisonia tcsniata, A. d'Archiac & E. de Verneuil, 1841, Bull. Soc. geol. 

 France, ser. 1, vol. xii. p. 160 ; iid. 1842, Trans. Geol. Soc. ser. 2, rol. vi. pt. ii. 

 p. 358 ; H. G. Bronn, 1848, Index Paheont. p. 748 ; L. G. de Koninck, 1851, 

 ' Descr. Anim. foss. du Terr. Carb. de la Belgique,' Suppl. p. 698, pi. lviii. 

 fig. 12 ; J. Morris, 1854, Cat. Brit. Foss. p. 259 ; J. J. Bigsby, 1878, ' Thes. 

 Dev.-Carb.' p. 327; R. Etheridge, 1888, 'Foss. of Brit. Islands,' vol. i. 

 Palaeozoic, p. 302. 



Shell conical, elongated, composed of more than four whorls. 

 Whorls convex, flattened rather below the middle by a broad level 

 band. This band is slightly depressed below the surface of the shell, 

 and is bounded on each side by two grooves. Lines of growth 

 curve backwards to the band above, and are obscure both on the 

 band itself and below. Sutures deep. Mouth unknown. 



There is but one specimen of this shell in the Gilbertson Collection 

 in the British Museum (Natural History), and I have not met with 

 any others that can be clearly identified with it. The surface is so 

 badly preserved that it is impossible to say whether there was really a 

 sinus in the oater lip, and whether consequently the flat band on the 

 whorls represents its position and is formed by the gradual and 

 successive filling up of the sinus. We cannot, therefore, decide 

 whether this species should be referred to the genus Murchisonia or 

 whether it is more nearly allied with the American forms, Turritella (?) 

 Stevensana, Meek & Worthen, 1 and Turbonilla Swallowiana, Gein., 2 

 where there is no sinus, but the lines of growth are merely strongly 

 curved. These American shells have since been referred by De 

 Koninck to the genus Aclisina. 3 Of the other species of this genus 

 A. striatula, De Kon., has the most strongly curved lines of growth. 

 The species under discussion differs, however, from these in showing 

 no traces of the numerous spiral threads with which their surface is 

 ornamented ; the whorls also are not so convex, and they are decidedly 

 flattened about the middle by a broad band. I therefore place this 

 shell in the genus Murchisonia provisionally. 



D'Archiac and De Verneuil 4 mention a Devonian shell which 

 they ' have some doubt in referring to this species ' as it is too 

 much worn for positive identification, and they do not figure it. 



Length of specimen, of which only four whorls are preserved, = 

 24 millim. ; width = 20 millim. 



Locality. Not known. 



Formation. Carboniferous Limestone (d 2 ). 



Section Ceeithioides, Haughton. 



Mekchisonia (Ceeithioides ?) Oweni, sp. nov. (PL X. fig. 1.) 



Shell conical, composed of more than five whorls. Whorls strongly 

 angular below the middle, slightly angular above, just below the 

 suture, flattened both above and below the strong angle. On the 



1 Geol. Surv. Illinois, ' Palaeontology,' vol. ii. (1866) p. 382, pi. xsvii. figs. 8, 



' Carbonforrnation unci Dyas in Nebraska,' 1866, p. 5, pi. i. fig. 19. 

 Ann. Mus. Roy. Hist. Nat. Belgique, ' Faune du Calc. Carb. de la Belgi 



vol. vi. (1881) pt. iii. p. 86. 



4 Trans. Geol. hoc. ser. 2, vol. vi. (1842) pt. ii. p. 358. 



