290 MR FRANK E. BEDDARD 



AFFINITIES OF PHREODRILUS. 



This very remarkable genus does not fit in perfectly with any single one of the 

 known families of Oligochaeta. The characters of the setae remove it from any of these 

 families, and are alone sufficient far the creation of a new family. 



The elongated setae of the dorsal rows agree fairly closely with the " Haarborsten" 

 of the Tubificidae, many Naids and Aeolosoma, but the ventral setae have an altogether 

 peculiar form. 



Turning to internal characters, the same difficulty is met with in referring Phreo- 

 drilus to any of the seven well characterised families into which the aquatic Oligochaeta fall. 



The single pair of funnels opening into the Xlth segment, recalls the Enchytraeidae ; 

 but, as Michaelsen has pointed out the variability of the position of these essential 

 organs in closely allied forms, Phreodrilus may be also compared in these particulars to 

 the Tubificidae and the lower forms generally. The long atrium, apart from the curious 

 sac in which it is enveloped, is perhaps more like that of the Tubificidae, but it is not 

 furnished with a prostate, nor with a penis. # However, in Ilyodrilus both these structures 

 appear to be wanting. Although this latter genus is included by Stolc in his recent 

 Monograph of the Bohemian Tubificidae [5], it is placed in a special sub-family. I 

 imagine that if it were not for the position of the genitalia, the worm would be referred 

 to the Naidomorpha. 



The ciliation of the entire alimentary canal, with the exception only of the buccal 

 cavity, is an important point of resemblance between Phreodrilus and the Naidomorpha, 

 as well as other lower families of Oligochaeta. 



In short, it does not seem to me to be possible to refer this genus to any known 

 family, without extending the definition of that family so as to include many of the 

 peculiar characters of Phreodrilus. 



I therefore propose the following definition of a new family, which is compiled on 

 the same lines as Vejdovsky's definitions of the remaining families of aquatic Oligochaeta. 



Fam. Phreodrilidce, n. fam. 



Setae in four rows ; the dorsal setae long and capilliform, two to each bundle in the 

 anterior segments ; only one posteriorly. Ventral setae of two kinds — one of each kind in 

 each row — curved and S-shaped without notched extremity. 



Testes in X and XI forming a continuous mass on each side, perforating septum 

 X/XI ; ovaries in XII ; development of ova as in Enchytraeidae and Ilyodrilus ; 

 sperm duct much coiled, opening by an atrium also much coiled on to segment XII ; 

 atrium and the greater part of sperm duct inclosed in a muscular sac derived from 



* Since the above was written, I have received a more fully adult specimen, in which one of the segments in the 

 neighbourhood of the Xlllth was furnished with a pair of tubular processes. An unfortunate accident in the prepara- 

 tion of this specimen for section cutting prevented me from ascertaining whether these are merely the everted atria, 

 as I believe, or are penes. The clitellum in this specimen apparently occupied about four segments, commencing at 

 the Xllth or Xlllth. 



