Vol. 54.] MISS J. DONALD OX THE GEI?US ACLISINA. 63 



the axis of the upper part of the spire bent at a small angle to the 

 lower part. 



Locality and Horizon. — The specimens mentioned above are all 

 from Law, Dairy, in the Lower Limestone Series (cf). Mr. James 

 Thomson has two examples from Cunninghambaidland. 



ACLISINA PFSILLA, sp. HOV. (PI. lY, figS. 14, 14 «, 5, & 15.) 



Description. — Shell slender, conical, composed of eleven convex 

 whorls. Protoconch consisting of one smooth whorl, coiled on the 

 same plane as the rest of the spire and not detached from it. 

 Whorls increasing gradually, ornamented by six or seven raised 

 threads, with an additional one on the body-whorl ; the uppermost 

 thread is generally the finest. The spaces between are about equal 

 with the exception of that between the two upper threads, which is 

 rather narrower. Sutures deep. Aperture rounded. Inner lip 

 reflected on the body-whorl. Columella simple, slightly thickened. 

 Base convex, imperforate. 



Resemblances. — This species differs from A. elegantula in having 

 a smaller spiral angle, fewer ornamenting threads, more evenly 

 •convex whorls, and a more depressed protoconch. It greatly 

 resembles A. parvula., but is distinguished by being more slender 

 ^nd having finer threads. 



Locality and Horizon. — The collections belonging to Dr. Hunter- 

 Selkirk, Dr. Young, Mr. Smith, Mr. Bennie, Mr. Neilson, and my- 

 self all contain specimens of this species. The largest example 

 belongs to Mr. Neilson ; its apex and base are both broken, leaving 

 only six whorls whose length = 4| mm. A portion of one whorl is 

 figured in PI. lY, fig. 15. It is from the Upper Limestone Series (d^) 

 at Glencart, Dairy. Some of the best-preserved examples are from 

 the Lower Limestone Series (cZ^) at Law, Dairy; four have the 

 protoconch intact (PL lY, figs. 14 a & h). That figured (PI. lY, 

 fig. 14) is in Mr. Smith's collection ; it consists of eleven whorls, and 

 is 4 mm. in length. 



External casts of this species also occur in an impure limestone 

 (the Shell Bed) of Yoredale age, at Widdle Fell, Wensleydale. 



ACLISINA TEREBKA, Sp. HOV. (PI. lY, figS. 16 & 16 a). 



Description. — Shell slender, very elongated, composed of more 

 than ten whorls. Whorls moderately convex, bead-like, high in 

 proportion to the width, increasing very gradually. Ornamentation, 

 consisting of seven raised threads ; the lowest appears just above 

 the suture, and is invisible on the higher whorls ; the two upper 

 threads are finer and somewhat nearer together than the lower. 

 Sutures moderately deep. Aperture and apex unknown. 



Resemblances. — There is a great likeness between this species and 

 A. pusilla, but it is more attenuated and the whorls are less convex ; 

 nevertheless it may possibly be a variety. It resembles A. aciculata 

 in its elongated slender form, but may be distinguished by the 



