DESCRIPTIONS OF GENERA AND SPECIES 219 



The brain lies in the first and second segments ; it has marked anterior and 

 posterior paired lobes. Behind the pharynx a circle of nervous cells surrounds the 

 oesophagus, as in Chaetogaster. 



Phreatothrix pragensis is the only species well known. It may be that Euaxes 

 baicalensis of GRUBE (4) is referable to the same genus, perhaps even to the 

 same species. It possesses a pair of papillae on the tenth segment (clearly the male 

 pores), and a pair of orifices on the eleventh segment, which I agree with VAILLANT 

 (6, p. 221) in considering to be spermathecal orifices. 



Phreatothrix pragensis, VEJDOVSKY. 



Trichodrilus pragensis, VEJDOVSKY, SB. Bb'hm. Ges. 1875, p. 196. 

 Phreatothrix pragensis, VEJDOVSKY, Z. Wiss. Zool. 1876, p. 541. 



Definition. Length, 40 mm. ; number of segments, 80. Prostomium twice as long as bnccal 

 segment, obtuse ; Jive anterior segments bi-annulate. Hab. Prague, in wells. 



To give any other characters in definition of this species would be merely, in 

 the present state of our knowledge, to redefine the genus. 



Genus CLAPABEDILLA, VEJDOVSKY. 



Syn. Lumbriculus, CLAPAREDE. 



Pseudolumbriculus, DIEFFENBACH. 



DEFINITION. Setae not bifid; both pairs of contractile perivisceral vessels with 

 caecal appendages ; spermathecae in IX. 



I have already gone into the question of the probable identity of VFJDOVSKY'S 

 genus Claparedilla with CLAPAREDE'S Lumbricidus (see p. 211). The genus has been 

 exclusively studied by the two writers whose names have just been mentioned. 



CLAPAREDE stated that the setae are ' simple, or indistinctly bifid ' ; but VEJDOVSKY 

 found in the species studied by himself, and also in CLAPAREDE'S species, that the 

 setae did not show any bifurcation ; this slight point of difference, for, after all, 

 CLAPAREDE is not very decisive upon the matter, should not, perhaps, be made too 

 much of. The vascular system is very characteristic of the genus, but appears to 

 differ a little in the two species ; the details will, therefore, be reserved until the 

 species are described ; but, in the meantime, it may be pointed out as characteristic 

 of the whole genus that both pairs of branches of the dorsal vessel are provided 



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