566 MISS J. DONALD ON NEW AND LITTLE-KNOWN 



greater ; in these points it resembles M. quinquecarinata, De Kon., 

 so that it appears to be a connecting-link between the two forms. 

 Only four and a half whorls are preserved, of which the length is 

 11 millim. 



A shell in the Museum of the Geological Society of London, from 

 the Carboniferous Limestone of the shores of Lough Gill, Co. Sligo, 

 may be this species, though the space above the angle is not quite 

 so great as in the type. 



In the collection of Mr. Young, Hunterian Museum, Glasgow, 

 there are several specimens which, though of much smaller dimen- 

 sions, appear to agree with this species in general characteristics. 



One (PI. XYI. fig. 6) from the shales of the Lower Limestone 

 Series ^ at Craigenglen, Campsie, has a length of 4| millim. Others 

 are from the shales of the Upper Limestone Series at Glencart, 

 Dairy, and at Robroyston. 



Some external casts in my own collection from the Yoredales of 

 Widdle Pell, Wensleydale, may also be referred to this species. 



MURCHISONIA (HyPEEGONIA") QUINQUECARINATA, De KoU., Var. PUL- 

 CHELLA. (PL XYI. fig. 7.) 



Murchisonia quinquecarinata, De Koninck, 1883, ' Paune du 

 Calc. Carb. de la Belgique,' vol. viii. pt. 4, p. 23, pi. xxxiv. figs. 

 14-16. 



Shell very elongated, turreted. Whorls angular, numerous. Angle 

 situated rather above the middle of the whorl. Ornamentation con- 

 sisting of a strong keel on the angle with two finer keels above and 

 three below; these latter are all visible above the sutures on the 

 five lower whorls, but the lowest keel is hidden on the upper part 

 of the spire. Spaces between the keels about equal in width. 

 Lines of growth not perceptible. Sinual band probably between 

 the keel on the angle and that next above. Sutures deep and 

 somewhat oblique. Mouth longer than wide. Ease slightly pro- 

 duced. Columella rather arched. 



I know of only one specimen, and this was given me by Mr. Young. 

 The apex is broken, and only eight whorls remain. 



Length 8| millim. ; width of lowest whorl 2| millim. 



From the above description it may be seen how strongly this 

 shell resembles M. quinquecarinata, De Kon., in ever}' way except 

 in size, for De Koninck gives 20 millim. as the length of his species 

 and 5 millim. as the width. He only speaks of two keels below 

 the angle on the whorls of the spire, and two additional keels on 

 the body-whorl, but some of the specimens examined in the Brussels 

 Museum show a third keel just above the suture on several of the 

 lower whorls similar to the specimen under discussion. The angle 

 is, however, placed high up the whorl on all the Belgian shells. 



^ The higher members of the Lower Carboniferous rocts which are known 

 to Scottish geologists as the Lower Limestone Series, the Lower Coals and 

 Ironstones, and the Upper Limestone Series, are now known to represent the 

 upper part of the Mountain Limestone and the Yoredale rocks of English 

 geologists. 



