56 MISS J. DONALD ON THE GENUS ACLISINA. [Feb. 1 898, 



and consists of eleven whorls in a length of 4| mm. It occurs in 

 arenaceous shale at Cullion, Draperstown, about the horizon of the 

 lower part of the Carboniferous Limestone. 



Locality and Horizon. — The largest specimen (PI. Ill, figs, 6 & 6 a) 

 is from the Carboniferous rocks (cZ^) at Penton ; it consists of 

 thirteen whorls, the apex is broken, and there are traces of three 

 additional whorls in the matrix. Its length = 8 mm., width 

 = 2| mm. I have also several smaller specimens from the same 

 locality. Other examples are found in the Lower Limestone 

 Series (cP) at Law, Craigenglen, Capelrig, High Blantyre, and 

 Brankam Hall ; this last place is the ' Laurieston ' of Ure. It 

 occurs in the Upper Limestone Series {d^) at Glencart, Dairy, and 

 at Boghead, Hamilton ; also in the Calciferous Sandstone {d ") at 

 Randerstone, Fife. 



The variety varians is from the Lower Limestone Series (d ^) at 

 Craigenglen and Capelrig, as well as from Laurieston. The variety 

 cingulata is found in the Lower Carboniferous at Penton ; the 

 Lower Limestone Series {d^) at Craigenglen, Crawfield, and 

 Capelrig ; and also in the Upper Limestone Series (cP) at Glencart 

 and Boghead. A specimen from Penton measures 5| mm. in length 

 and 1| mm. in width. Another individual (PI. Ill, figs. 10 & 10 a) 

 is from Glencart. Its length = 3 mm. 



ACLISINA COSTATULA, DoU. (PI. Ill, figS. 12-15.) 



Aclisina costatula, J. Donald, 1885, 'Carb. Gaster. from Penton, etc' Trans. 

 Cumberl. & Westmorl. Assoc, no. ix, p. 133 & pi. ii, figs. 5 & 5 a. 



Terehra or Turbo clavicula longissima (pars), D. Ure, 1793, 'History of Ruther- 

 glen & E. Kilbride,' p. 308, pi. xiv, fig. 11. 



Turritella elongata (pars), J. Fleming, 1828, ' Brit. Animals,' p. 305. 



Description. — Shell small, slender, conical, composed of about 

 fourteen whorls in the adult. The protoconch consists of about one 

 complete smooth revolution, nearly orbicular in outline, detached 

 from the highest whorl of the spire below, with which it forms an 

 acute angle ; its junction with the conch is indicated by a faint rib. 

 Whorls more or less convex, increasing gradually. The lower part 

 of the whorl is ornamented by five threads ; the two upper are 

 generally the strongest, but sometimes the third is equally strong; 

 the lowest is the finest, and is frequently hidden beneath the suture 

 on the higher whorls ; there are occasionally one or two additional 

 fine threads on the body-whorl. On the upper part of the whorl 

 there is a fine thread below the suture, which is sometimes absent ; 

 the widest space lies between it and the uppermost of the five 

 threads. Aperture rounded. Columella simple, nearly straight. 

 Inner lip refiected on the body-whorl. Base convex. Umbilicus closed. 



Besemhlances. — This shell resembles A. elongata, Plem., but the 

 keels with which it is ornamented are stronger and less numerous, 

 and the spiral angle is smaller. It also bears a likeness to A. pulchra 

 var. intermedia^ but is still more slender and less robust. It is 

 somewhat similar to A. hellilineata, Miller ; the figure of this species 

 is not, however, sufficientlj" distinct for accurate comparison. 



