Vol. 54.] MISS J. DONALD ON THE GENUS ACLISINA. 51 



from the Upper Coal Measures as probably of Permian age. The 

 genus is, however, older than the Carboniferous, for two Devonian 

 species have been described : one. A, longissima, by the Rev. G. 

 F. Whidborne from the Pilton Beds, the other, A. multicristata, by 

 D. P. (Ehlert from France. 



It appears to have been most numerous in the Carboniferous 

 Period, and I am here describing fourteen British species and five 

 varieties of that age. Some of these have been previously described, 

 though not always referred to Adisina, namely: — A.elongata, Flem.; 

 A. costatula, Don.; A. grantonensis was referred by E,. Etheridge, 

 Jun., doubtfully to Murchisonia striatula, De Kon., as was also 

 A. tenuistriata by me ; Loooonema sulcatula, M'Coy, has the ap- 

 pearance of a species of Aclisina, but it is known only by somewhat 

 imperfect moulds of the exterior; Loxonema polggyra, M'Coy, is 

 probably identical with one of the varieties of A. elongata, Flem. ; 

 Turritella triserialis, Phil.,^ and T. acicula, Phil.,^ may possibly 

 belong to this genus, but the types appear to be lost, for they 

 are not in the Gilbertson Collection. There is one specimen in 

 this collection marked T. acicula from Otterburn, but it is not the 

 type, and the surface is too imperfect to discern what it really is. 

 A. pulchra, var. tenuis, De Kon., has not hitherto been recorded 

 Bs a British species. 



In Belgium there have been described A, pulchra, De Kon., and 

 the variety tenuis, De Kon. Another species, A. gemmata^ has 

 been figured by De Koninck, but not described ; the lines of growth, 

 however, on the figure appear to be too straight for Aclisina. 



Eichwald ^ describes and figures two small spirally-striated shells 

 from E-ussia as Turyitella acus and T. sjoiculuin which should pro- 

 bably be referred to this genus. 



In America nine Carboniferous species have been described 

 which may belong to Aclisina, namely, Aclisina hellilineataf Miller, 

 Aclis rohusta, Stevens, A. minuta, Stev., Aclis (?) Stevensoni, 

 White, Murchisonia minima^ Swallow, Turritella 1 Stevensana, Meek 

 & Worthen, Loxonema quadri-carinatum, Worthen, L. acutula^ 

 Dawson, and Turhonilla Swallowiana, Geinitz. Of these A. helU- 

 lineata, Mill., Aclis rohusta, Stev., and Turritella (?) Stevensana, 

 M. & W., are represented as having the sigmoidal lines of growth 

 and lineated whorls characteristic of Aclisina. In Turhonilla 

 Sivallowiana, Gein., the greatest sinuosity of the lines of growth 

 appears to be situated lower on the whorls than in the typical 

 Aclisina. The lines of growth are not given on Loxonema 

 acutula, Daws., nor on L. quadri-carinatum, Worth. ; the former 

 has the general appearance of Aclisina, but the latter has more 

 flattened whorls than usual, and may possibly belong to the genus 

 Orthonema, Aclis (?) Stevensoni, White, greatly resembles A. rohusta^ 

 Stev. No figures are given of Murchisonia minima, Swall., nor 

 -of Aclis minuta, Stev. 



^ 'Geol. Yorks.' vol. ii (1836) p. 229 & pi. xvi, fig. 25, 



2 Ibid. p. 229 & pi. xvi, fig. 23. 



3 ' Faune Oalc. Carb. Eclg.' vol. viii, pt. iv (1883) pi. xxxiii, figs. 43 & 44. 

 * ' Leth. Boss.' vol. i (186U) pp. 1120, 1121 & pi. xlii, figs. 4 & 5. 



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