President's Address. G3 



The third genus of tliis family, Macrocheilus, was originally 

 described* by the late Professor Phillips, for a series of 

 thick, smooth, subglobose or oval shells with convex whorls, 

 and an oval aperture, the columella flattened, imperforate, 

 and witli an obtuse revolving fold. Six species are known 

 from the Carboniferous series of North Britain. One or two 

 of these appear to vary to that extent that it is difficult to 

 determine where the one begins and the other ends. One 

 very well-marked character appears to exist throughout the 

 genus, the invariably sharp apex of the spire, whether of the 

 elongated or depressed form of the genus.t In a recently 

 described species, M. semistriatus (A. and Y.), the body-whorl 

 is smooth, and the upper ones striate, not a usual feature in 

 this genus. 



If we strictly adhere to precedence in synonomy, the name 

 Macrocheilus (Phillips, 1841) appears to be subsequent in 

 date to that of Macrocheihts (Hope, 1838), proposed as a 

 genus of Coleoptera, and is, therefore, ineligible. Such is 

 Professor de Koninck's view, J but I think in this case, that 

 " use and wont " has so long retained the name, that it might 

 be allowed to stand. In place of Macrocheilus (Phill.), M. E. 

 Bayle has proposed that of Duncanicc,^ a very inappropriate 

 name, but finding this pre- occupied for a genus of corals, 

 changed it to Macrochiliiia^W and in this sense it is used by 

 Professor de Koninck. 



Since the publication of the " Catalogue of W. Scottish 

 Fossils," Messrs Armstrong and Young,ir and again Mr J. 

 Young,** have pointed out the existence in the Eobroyston 

 deposit, and also in the L. Limestone shales, of two shells 

 provisionally identified with FAenchus antiquus (M'Coy), and 

 E. subulatus (M'Coy). They are chiefly distinguished from 

 Macrocheilus by the presence of a tooth on the pillar lip, in- 



* Pal. Foss. Devon., p. 103. 



+ Meek and Wortlien, Illinois Geol. Report, ii., p. 368. 



J Gasteropodes, Op. cit., p. 28. 



§ Jour, de Coucliyliologie, 1879, xxix., p. 35. 



II lUd., XX., p. 241. 



II Trans. Geol. Soc, Glasgow, iv., p. 278. 



** Trans. Geol. Soc, Edinb., 1881, iv., pt. 1, p. 90. 



