70 MES. JAXE LO]S'GSTAFF OX [vol. Ixxiii, 



AcLISIJs^A FABEB, sp. IIOV. (PI. Y, tlgS. 4 & 5 «-5 C.) 



Diagnosis. — Shell small, conical, composed of more than nine 

 whorls. Whorls broad, convex, slight^ flattened above and sub- 

 angular near the middle. Lower part ornamented by six moderately 

 strong threads with two additional ones on the body-whorl; upper 

 part ornamented b}^ three fine threads ; base covered b}^ numerous 

 still finer ones. Protoconch composed of little more than one 

 smooth volution, moderately raised and slightly overhanging the 

 succeeding whorl. Aperture subcircular. Columella nearly straight. 

 Inner lip reflected. 



Remarks. — This species somewhat resembles A. jnilcJira, but 

 it has more convex whorls ornamented by finer and more numerous 

 threads, also the protoconch is more orbicular and not so erect. 

 ^—Holotype. — The larger specimen re^Dresented in PI. \, fig. 4, 

 must be regarded as the holotype ; it consists of nine whorls the 

 length of which = 6 mm., and 'the Avidth^2*5 mm. The smaller 

 shell (fig. 5) is remarkable for having the protoconch intact; its 

 length = l-75 mm. Both are in Mr. John Smith's collection. 



Locality and horizon. — High Smithston, Kilwinning (Ayr- 

 shire), in the Upper Limestone Series. 



Three small shells in my own collection appear to belong to this 

 species. They are from Grlencart, Balry, also in the Upper Lime- 

 stone Series. 



Aci.TSiXA cosTATULA Donald. 



Aclisina costattda Donald, 1898, op. cit. p. od & pi. iii, tigs. 12-14. 



Holot^^pe. — Oj). cit. pL iii, rig. 12. Longstaft: Collection. 

 Localit}^ and horizon. — Penton Linns, Liddel Water (Dum- 

 friesshire). LoAver Limestone Series. 



Aclisina costatula, var. dubia Donald. 



Aclisina costattda var. dubia, Donald, 1898, ojj. cit. p. 57 & pi. iii, tig-. 15. 



Remarks. — The examination of a large number of specimens 

 shows that A. cosfatula exhibits a certain amount of variation. I 

 suggested the name duhia foi* a large variety having somewhat 

 higher whorls. Unfortunately the original example has perished 

 by fire with the late Mr. Thomson's collection. There is, however, 

 a shell in Mr. J. Smith's collection greatly resembling it in every 

 way. It 'has six whorls intact, Avhich have a length of oo milli- 

 metres. 



Locality and horizon. — AVhereas the original was from 

 Craigenglen, Campsie (Stirlingshire), in the Lower Limestone 

 Series, this s^^ecimen is from ]Moss ^Nfullock, in the L^pper Lime- 

 stone Series. 



Aclisina attenuata Donald. 



Aclisina attenuata Donald, 1898, op. cit. p. 58 & pi. iv. tigs. 2-3. 



Holotype. — Oj). cit. pi. iv. tig. 2. Longstaff Collection. 

 Localit}' and horizon. — Glencart, Dairy, in the Upper 



Limestone Series. 



