134 



Transactions of the Society. 



supplied, as it was intended at an early date to publish the 

 diagnosis in one of the scientific journals. 



Pig. 17. — Achseta incisa sp. n. 



1. Brain incised, typical. 2. Brain convex behind. 

 3. Nephridium. 4. Spermatheca. 



The British species of Achseta now number six, and may be 

 distinguished by the following characters : — g 



1. Seta? sacs absent . 



2. Seta? sacs present 



( Sacs present ventrally and dorsal ly 

 ' (Sacs present dorsally only 



. J Brain concave behind 

 ( Brain convex or oval : 



a. Spermatheca? with pear-shaped ampulla A. bohemica 



(3. Spermatheca? like spermatophores . A. spermatophora 



y. Spermatheca? simple ducts . .A. minima 



