T9C)S. 255 



ELUMA PURPURASCHNS. 

 A WooDLOusE New to the British Isles. 



BY DENIS K. PACK-BERESFORD, B.A., M.R.I. A. 



(PI.ATE 10.) 



Ix the October number of the Irish Naturalist (p. 206, supra), 

 I recorded the capture during the latter half of the month of 

 August last, of a large number of specimens of what I believed 

 to be an ArmadiUidiunij on the southern cliffs of the Hill of 

 Howth. Dr. R. F. Scharff, who has most kindly made inquiries 

 for me into the identity of this species, now informs me that 

 it proves to be not an Armadillidium, as I had thought, but 

 to be referred to the closely allied genus of Eluma. 



This genus, which until quite lately contained only the 

 single species E. purpurasceiis^ was described by Prof. Budde- 

 Lund in his work on '* Crustacea Isopoda Terrestria," 

 published in 1885, and though closely related to the genus 

 Armadillidium, has not previoush^ been found in the British 

 Isles. It may perhaps be remarked here that Prof. Budde- 

 Lund distinguished these two genera — Armadillidium and 

 Eluma — from Armadillo and other allied genera by the 

 presence of the very broad and flattened uropods, which in 

 the latter genera are small and rounded. 



The characteristics which distinguish Eluma from Arma- 

 dillidium will be apparent from the following translation of 

 Prof. Budde-Eund's definition of the genus : — 



ElyUMA. 



The exterior auteniiLe slightly shorter than half the leugth of the 

 hod), hairy. The second segment of the scape wider but hardly lougei 

 than the fourth segment ; flagellum biarticulate. 



The interior antennae conical, very small. 



The eyes simple, very small. 



The upper margin of the clypeus plain, not lobed. 



The triangular frontal lobe depressed in the middle, forming on each 

 side, with the prominent oval lateral lobes, the groove for the anteuuLL-. 



The vertical marginal line reaching the frontal line. 



The lateral plate of the first body-segment slightly divided behind. 



The telson nearly triangular. 



The exopodites of the first and second pairs of pleopods modified as 

 trachese. 



The uropods short, equal in both stxes, extending beyond the telson, 

 but not beyond the lateral plates of the penultimate segment : the 

 basal segment wide, oblique, four-sided, very unequally divided ; the 

 terminal segment laminate and tlattened. 



