Yol. 54.] MISS J. DONALB ON EHABDOSPIRA. 65 



worn, appears to show traces of finer threads intercalated between 

 the coarse ones. The lines of growth are very indistinct, so that it 

 is impossible to refer it to any genus with certainty, and I merely 

 place it in Aclisina provisionally and reproduce the figures for the 

 sake of comparison with other forms. 



The largest shell shows about eight whorls, whose length = 14 

 mm., width = 5 mm. 



The specimens are in the Museum of Science and Art, Dublin. 



Locality and Horizon. — Carrickroughter, Kesh. Yellow Sand- 

 stone (d^). 



Subgenus Ehabdospira nov. 



Shell of moderate size, conical, composed of numerous convex 

 whorls, which are ornamented by spiral threads or keels. Outer lip, 

 as indicated by the lines of growth, very slightly sigmoidal. Aper- 

 ture and protoconch unknown. 



Resemblances. — This subgenus greatly resembles the genus 

 Aclisina in form and ornamentation, but it is distinguished from 

 that genus by the contour of the outer lip, which is much less sig- 

 moidal and not so prominently produced in front. 



I know of only two species which are referable to it, and they 

 occur as external casts, so the whole structure of the shell itself is 

 unknown. These species are Rh. compacta and Rh. SeJJcirJcii. The 

 outer lip of Rh. compacta is still less sigmoidal than that of Rh. Sel- 

 JcirJcii, and none of the whorls are plicated as in that species. These 

 distinctions are hardly sufficient to warrant their separation in 

 different genera, especially as our knowledge of them is incomplete. 

 I therefore group them together for the present. 



Rhabdospiea Selkiekii, sp. nov. (PI. Y, fig. 4.) 



Description. — Shell elongated, turreted, composed of numerous 

 whorls, which are convex, very prominent in the middle, high in 

 proportion to the width, gradually increasing. Ornamentation 

 consisting of eight strong raised threads with nearly equal spaces 

 between, except in the middle of the whorl, where the space is 

 rather wider and has either two or three finer threads down it ; there 

 is also a fine thread intercalated in one space above and two spaces 

 below the middle. Sutures deep. Lines of growth somewhat sig- 

 moidal, and but slightly arched below. On the penultimate whorl 

 there are faint ribs or plications following the course of the lines of 

 growth- Aperture and protoconch unknown. 



Resemblances. — There is but one specimen of this species, which 

 is in the collection of Dr. Hunter-Selkirk, and it is a mould of the 

 external form in limestone. In appearance it somewhat resembles 

 Aclisoides striatula, De Kon., but the lines of growth show no indi- 

 cation of a sinus in the outer lip, the whorls are more convex and 

 the sutures deeper. The figure (PI. Y, fig. 4) is drawn from a wax 

 impression ; there are but four Avhorls and a portion of a fifth, the 



Q. J. G. S. 1^0. 213. P 



