236 Dr. F. E. Beddard on the Genus Trichodrilus. 



that he is right in denying one to Trichodrilus? It is true 

 that Claparede, as Vejdovsky says, neither mentions nor 

 figures such ; but, though present and obviously protrusible 

 in ray Trichodrilus icenorum, it is not ve*y conspicuous, and 

 would probably be overlooked in examples studied without 

 the aid of microscopic sections. My species, in addition to 

 the penis, has two pairs of spermathecae, and thus would be 

 intermediate between the two genera. A possible difference 

 is not referred to by Vejdovsky, and that is the thick 

 muscular walls of the atrium figured by Clapaiede and the 

 much thinner atrial walls figured by himself in Phreatothrix. 

 I have no notes as to the state of affairs in Phreatothrix 

 cantabrigiensis, but I have already referred to this matter 

 above, and may here point out that Piguet * figures such an 

 atrium in Trichodrilus sanguineus, which, on account of its 

 single pair of spermathecse " should be " a Phreatothrix. I 

 am disposed to follow Michaelsen in fusing these two genera. 



Note on a possibly second British Species of Trichodrilus. 



A third example of Trichodrilus, which I examined by 

 longitudinal sections, was not put aside by me as a probably 

 second species of the genus ; but on microscopical study it 

 shows certain differences from those upon which the above 

 account of Trichodrilus icenorum was mainly based. 



As I am unable to give more than an account of the repro- 

 ductive system, I hesitate — for reasons which will be explained 

 — to refer it definitely to a second species, and therefore do 

 not give it a name. 



Inasmuch as this worm has two pairs of testes in IX., x., 

 one pair of ovaries in XI., sperm- duct funnels in IX., X. 

 opening into an atrium which itself opens on to the exterior 

 in segment X., an oviduct funnel in XI. opening on to the 

 segmental border-line Xi./xil., two pairs of spermathecse 

 lying in XI., XII., and, finally, that it was found with others 

 showing. exactly the same characters and described above, it 

 would seem impossible to create for it a new species. 



Nevertheless, the atrium and sperm-ducts show marked 

 differences from those of the type-specimens of Trichodrilus 

 icenorum, which are as follows : — The atrium consists, as in 

 the others, of a nearly spherical sac communicating with the 

 exterior by a much narrower duct. It has a wall, which is, 

 however, very much thinner than that of the others, though 

 it is composed of precisely the same layers. It is lined by 



* Rev. Zool. Suisse,^, c. 



