62 Proceedings of the Royal Physical Society. 



relation to Orthonema, but that they are not true Loxa/iemce, 

 I think we may take for granted. 



A third species, peculiar to Scotland, L. clathratula (Y. and 

 A.), is ornamented with spiral ridges, intersected by longi- 

 tudinal costce, but the details of the aperture are not suffi- 

 ciently known to determine the section to which it belongs. 

 Professor de Koninck has recently divided the Carboniferous 

 Loxonemm into two sections — the Icevigata, or smooth, and 

 the costata, or ridged.* 



Again, another genus, although Devonian and not British 

 so far as known, may be referred to here as presenting a 

 further modification of the Loxonema. type. I refer to 

 Michelia of F. A. Eoemer,*!- in which the shell is elongately 

 conical, the body-whorl very much shorter than in a true 

 Loxonema, with sharply-turned lines of growth, and a very 

 much bent outer lip. 



As intermediate between Loxonema, and the following 

 genus MacTocheihis, we may consider Polyphemoipsis (Port- 

 lock). J The latter author included under this name elongated, 

 mitra-like, non-umbilicated shells, with an elongated mouth, 

 smooth polished surface, sharp spire, and no wave in the 

 outer lip. One species is met with in the Carboniferous 

 rocks of Scotland, P. fusiformis (Sby.),§ but is usually much 

 stunted when compared with the individuals found in Eng- 

 land. It is quite possible that the Eulima Phillipsana (De 

 Koninck) II is referable here, when the number will be in- 

 creased to two, although the mouth in this shell approaches 

 more to that of typical Loxonemce. The present genus may 

 be distinguished from Loxonema, by having a truncated base 

 to the columella, and the smooth surface ; from Macrocheilus 

 in wanting the callosity and fold, or revolving ridge of the 

 columella seen in that type.lF 



* Gast^ropodes, op. cit., pp. 41 and 51. t Palreontographicn, iii., p. 73. 



+ Geol. Keport, Londonderry, 1843, p. 415. 



§ Trans. Geol. Soc, 2d series, v., Expl., pi. 39, f. 26. 



II Anim. Foss. Terr. Garb. Belgique, p. 471. I find that Professor de 

 Koninck has, in his recent work, "Fauna du Calcaire Carbonif.," pt. 3, p. 

 63, published after the above remarks were written, definitely placed this 

 species in Polyi^hemopsis. 



H Meek and Worthen, Illinois Geol. Report, ii., p. 373. 



