133 



while the spaces between the five or six keels on the lower part of 

 the whorl are much narrower. The two uppermost keels are the 

 slightest, and they are occasionally absent. This variation in the 

 disposition of the keels is observed on different individuals occur- 

 ring in the same stratum. The lines of growth are not very 

 distinct, but they are visible under a magnifier. The mouth is 

 nearly round. 



This shell was figured by the Rev. David Ure {^History of 

 Rutherglen and East Kilbride, PI. xiv., fig. ii, 1793.) It was 

 afterwards briefly described by Fleming as Turritella elongata, {Brit. 

 Animals, p. 305, 1828.) It is entered as T. elongata, Flem., by 

 Morris in his Catalogue of Brit. Foss., 2nd Edn., p. 284. 



Length of specimen figured, 6 J mm.; width of body whorl, 

 about 2 mm. The shell figured is slightly flattened by pressure. 

 Another specimen is 8^ mm. in length, it has thirteen whorls, and 

 the apex is broken. It would probably have three more whorls if 

 perfect. It also is slightly flattened by pressure. Shells of nine 

 to eleven whorls are most abundant ; those of greater size being 

 comparatively rare. 



Locality and Horizon. — I have found about a dozen specimens 

 of this species in the Calciferous Sandstone Series at Penton ; and 

 small specimens abound in the shales of the Lower Limestone 

 Series at Capelrig, East Kilbride. It also occurs in the same beds 

 at High Blantyre and Craigenglen, and also in the shales of the 

 Upper Limestone Series at Glencart, Dairy. Small casts occur on 

 Widdle Fell, which seem to be identical with this species. 



AcLisiNA COSTATULA, sp. nov., PI. II., figs. 5, ^a. 

 Shell small, elongated, slender, of thirteen to fifteen whorls, of 

 which the upper part is slightly flattened, and the lower convex. 

 There are four strong keels on the lower part of each whorl, and 

 frequently another slightly-finer one below, which is hidden beneath 

 the suture on the upper whorls. On the upper flattened part of 

 each whorl another keel is generally placed below the suture, and 

 between this keel and the uppermost of the others is the widest 

 space. This keel is occasionally absent. Lines of growth not 



