368 MR. F. E. BEDDARD ON A RARE [Apr. 28, 



V 



similar to that which has been described, foi' instance, by Stole in 

 Lophochceta^ , whose excellent figure of the same has been repro- 

 duced by myself in my ' Monograph of the Oligochseta ' t. This 

 system of capillaries was only to be clearly seen during the diastole 

 of the dorsal blood-vessel. 



In certain other minutife of structure the present examples also 

 do not agree with the species P. jjragensis ; for instance, I found in 

 several examples of my species that the investment of chloragogen 

 cells of the alimentary tract commences in segment viii. 



Yejdovsky mentions segment xii. as being that in which this 

 investment is first visible in Phreatothrix j)Tagensis. Vejdovsky 

 has mentioned that in the living worm the mouth-aperture is 

 seen to be covered with ciliated cells, the cilia being in active 

 motion. It appeared to me that this ciliation in my species 

 extended also on to the prostomium, but certainly not far on to that 

 part of the body. It was in any case very clearly visible in the 

 mouth and just at its outside. This state of afiiairs was, however, 

 quite unrecognisable in one of the two specimens in which I 

 particularly studied it. It is not very easy to miss actively 

 vibratile cilia in this position, so that I am confident in my 

 assertion that there was no active ciliation in one specimen. 

 Whether this is a variable character in the species or was due to 

 temporary cessation of movement % I am unable to say. 



The nepJiridia of Phreatothrix are in some ways remarkable. 

 Yejdovsky has pointed out that a single pair may occupy a 

 number of segments. I found precisely the same extension of 

 the nephridia through several segments in the examples which I 

 have studied. There is, however, some difference in the earlier 

 account given by Yejdovsky from the later account of the 

 nephridia of Phreatothrix pragensis which is important, in view 

 of the facts which I have noted in the position of the nephridia 

 of my own species of Phreatothrix. In the earlier paper on the 

 species (that in the ' Zeitschrift f iir wissenschaftliche Zoologie ') 

 he figures § two pairs of nephridia, a pair in each of segments vii. 

 and viii., each pair only occupying its own segment, though the 

 funnel of course lies in the segment in front. In the ' System 

 und Morphologic der Oligochseten ' |j he figures a pair which open, 

 indeed, on to the viiith segment, but which extend back as far 

 as the xivth. These are followed by another pair which open on 

 to the xivth segment, but which extend back as far as the xxist. 

 Both individuals figured are represented as sexually mature. It 

 may be that Yejdovsky had before him examples, not only of 

 Phreatothrix pragensis but also of the species with which I deal 

 here, and which I believe to be distinct from that. 



I have myself found a nephridivim on each side in segment vii, ; 



* Abhandl. Bohm. Ges. Wiss. (2) vii. (1889). 

 t Oxford, 1895, p. 241, fig: 41. 



X I kept the specimen under intermittent observation for most of a morning, and 

 supplied fresh water at times. 



§ Tom. cit. pi. xxxix. fig. 2. || PI. xi. fig. 18. 



