T9o8, Carpenter. — CoUembola neiv to the Britannic Fatcna. 177 



is provided with a double membrane (fig. 3 a) ; these characters 

 are not found in any other species inchided in Isotoma in its 

 wide sense. As the specific name implies, the mucro has two 

 teeth (fig. B, 4), which are sharp and prominent. 





Fig. B. — A ore?! /a bidejiticttlata — Yy side view X 27 ; 2, ocelH and post-an- 

 teniial organ of left side, x 375 ; 3, foot X 260 (t, tunica of claw, a, double 

 membrane of empodial appendage); 4, tip of dens and mucro, x 260. 



As Agren ('04) in his full description of this species has 

 pointed out, there is some fusion between the fifth and sixth 

 abdominal segments, The head bears on each side eight 

 ocelli, and the post-antennal organ is broadly oval in form 

 (fig. B, 2.) 



