A SURVEY OF THE GROUP 35 



great deal of its time out of water, and in Europe is often dug up 

 in gardens where it feeds on the earthworms. 



The Trematobdellidae and the Semiscolecidae merit only a 

 mention in passing. The former are similar to Erpobdellidae in 

 general structure, but have a duct from the mid gut to the body 

 wall. The latter are perhaps intermediate between the Hirudidae 

 and the Erpobdellidae, as they have only a single dorsal jaw rudi- 

 ment and very small crop caeca. The testes are frequently 

 subdivided. Opinions differ about whether they should be placed 

 in the Gnathobdellae or the Pharyngobdellae. 



