part 2] ACLisixA and aclisoides. 71 



ACLISINA DELICATULA, Sp. nOV. (PL Y, figS. Q Q-Q C.) 



Diagnosis. — Shell slender, composed of eleven gradually in- 

 creasing whorls. Whorls convex, broad and low. Ornamentation 

 consisting of five moderately strong threads on the lower part of 

 each whorl, with nmnerous additional finer ones below on the body- 

 whorl ; higher part of the whorl apparently smooth. Lines of 

 growth miknown. Apex broad and nearly flat. Protoconch con- 

 sisting of about one smooth whorl coiled on almost the same plane 

 as the rest of the spire to which it is attached. Base convex, but 

 little produced. No umbilicus. Aperture ovoid. Columella nearly 

 straight, curving round at the bottom to meet the outer lip. Inner 

 lip reflected on the body- whorl. 



Remarks. — This species resembles A. costatula in ornamenta- 

 tion, but the form is not so slender and the whorls are more 

 convex. The protoconch of the only known specinien is intact, 

 but is somewhat worn, and probably is slightly crushed, so that it 

 may not originally have been so flat. 



Holotype. — PL Y, figs. Qa-Qc. In my own collection, given 

 to me by the late Dr. John Young. 



Dimension s. — Length = 4-25 millimetres ; width =1-4 mm. 



Localit}^ and horizon. — Grlencart, Dairy, in the Upper Lime- 

 stone Series. 



AcLisiNA MicuLA, sp. nov. (PL Y, figs. 7 a & 7 b.) 



Diagnosis. — Shell elongated, composed of about ten slightly 

 convex whorls. Whorls broad, ornamented on the lower two-thirds 

 by four threads, the two upper are the strongest and farthest 

 apart ; two additional fine threads on the bod}- whorl. Sutures of 

 moderate depth. Base not produced. Aperture rounded. Proto- 

 conch flat and broad, attached to, or but slightlj^ raised from, the 

 spire. 



Remarks. — Aclisina micula may be distinguished from 

 A. costatula by its greater spii-al angle, shallower sutures, more 

 compactl}'- coiled whorls, and in the protoconch being attached to 

 the spire instead of standing up. It differs also from A. attenuata 

 in being less slender, and in the lower threads being coarser. The 

 only two specimens that I have met with show the protoconch 

 intact ; it adheres closely on one, while on the other (the holotype) 

 it is ver}^ slightly raised. 



Holotype. — PL Y, figs. 7 a &7 h. Smith Collection. 



Dimensions. — Length=8"5 millimetres; width = l mm. 



Locality and horizo n. — High Smithston, Kilwinning. Upper 

 Limestone Series. 



The other example is from Moss Mullock, Kilwinning, at the 

 same horizon and in the same collection. 



ACLI8INA siMiLis Donald. (PL Y, fig. 8.) 



Aclisina similis Donald, 1898, op. cit. p. 57 & pL iii, fig. 16, pL iv, fig. 1, 

 Aclisina pusilla Donald, 1898, pars, op. cit. p. 63 & pi. iv, fig. 15 [exclude 

 figs. 14, 14 a, & 14 J.] 



