42 EARTHWORMS AND THEIR ALLIES [ch. 



shore. They have four bundles of short often straight 

 and somewhat stumpy setae ; Anachaeta is entirely 

 without setae. That they bear some relation to the 

 lowest group of Oligochaeta, that of the Aeolosomas 

 and Naids, appears to be shown by the very anterior 

 position of the spermathecae, i.e. in the fourth or 

 fifth segment. The spermaries and ovaries on the 

 other hand are in segments xi and xu. They are 

 peculiar among the aquatic families in having complex 

 glands appended to the oesophagus which recall the 

 calciferous glands of the earthworms. The funnel 

 of the sperm duct is extraordinarily deep and lined 

 with glandular cells except in an apparently primitive 

 genus from Lake Baikal. 



The remaining family of the Limicolae is that of 

 the Haplotaxidae which contains two genera, viz., 

 Haplotaxis, better known as Phreoryctes, and Pelo- 

 drilus. These two genera overlap somewhat in their 

 characters and it is in the present state of our 

 knowledge rather difficult, if indeed possible, to 

 differentiate them thoroughly. They are slender 

 worms which frequent either damp earth or water 

 and are thus somewhat intermediate in habit between 

 the Limicolae and the Terricolae. The chief peculiarity 

 of their structure lies in the fact that the sperm ducts 

 are unprovided with any kind of terminal apparatus 

 whatever, but open directly upon the exterior. 

 Moreover there are generally two pairs of testes in 



