1908.] 



OLIGOCH^TE WORM IN ENGLAND. 



36r 



There is another important point in the structure of the- 

 vascular system in which I find that my species does not agree 

 with Phreatothrix pragensis. It is characteristic of the latter, as 

 of some other Lumbriculids, that the dorsal vessel in the intestinal 

 region gives ofi" a series of blindly ending transverse appendages, 

 which are contractile. >Such structures demand the living worm 

 for their successful demonstration. I examined several specimens 

 with great care in order to ascertain if these characteristic csecal 

 vascular trunks were to be seen ; and 1 utterly failed to see them. 



Text-fi2-. 77. 



Flireatothrix canta hrigiensis. 



Anterior end of dorsal and ventral vascular trunks. 



D. Dorsal vessel. | H. " Hearts." ] V. Ventral vessel. 



I cannot think that they were present in the greater part of the 

 intestinal tract, where I sought them in vain. I have the more 

 confidence in my ability to see these contractile appendages in 

 that I recognised the network of non-contractile vessels upon the 

 gut, which Yejdovsky does not record in Phreatothrix ijragensis. 

 These vessels formed a close lattice-work upon the gut, quite 

 Peoc. Zool. Soc— 1908, No. XXIV. 24 



