148 SOME FURTHER RESEARCHES 



the work of the Blood-worms, or larvae of Chironomtis^ and not of 

 Tub if ex ; and I can only repeat the statement in my note (Vol. I., 

 p. 15) that I have never been able to see the tubes stated to be 

 made by the latter. I cannot allow that the tracks which the 

 worms sometimes make, and which may remain for a few 

 seconds after their passage through the mud, are tubes, any 

 more than that the foot-prints of a man are his dwelling place. 

 These worm tracks show no consistency, and disappear almost 

 immediately with the least disturbance of the water, or even with- 

 out it. A tube must necessarily have some consistency. * 



With regard to the relations of the two fluids found in these 

 and other annelids, viz., the red vascular fluid and the colourless 

 corpusculated fluid occupying the perivisceral cavity, it may be 

 interesting to quote Prof. Lankester on this subject. He says : — 

 " It is not yet apparent which of the two fluids should be called 

 blood, and recognised as the homologue of that fluid in the 

 vertebrata. . . . The following view^ which tends to explain 

 this matter, and place it in a clear light, is put forward by my 

 friend. Prof Busk. In vertebrata the blood can be separated into 

 two parts — the red corpuscles and the clear white plasma with the 

 white corpuscles. The function of the red corpuscles, it is generally 

 admitted, is to carry oxygen ; it, in fact, is respiratory. The 

 function of the plasma on the other hand, with its white corpuscles, 

 is simply nutrient. Assuming that this is a correct view of the 

 case, since it is supported by many and conclusive facts, and, 

 indeed, is very generally conceded, let us turn to the Annelida. 

 We find a red fluid, undoubtedly devoted to respiratory purposes, 

 in many genera, and a colourless plasma, with white corpuscles, 

 bathing all the organs of the body. The conclusion is, obviously 

 enough, that the red vascular fluid represents simply the corpuscles, 

 whilst the colourless, corpusculated fluid is homologous with the 

 white plasma of vertebrated animals. It would be unsafe to draw 

 any conclusions as to the respective functions of the fluids from 

 this comparison. The functions of the two fluids in the annelida 

 have yet to be much studied ; all that zoologists at present appear 

 to be agreed upon being that, the red vascular fluid is the chief 



* If any of our readers can give me any information on the subject of 

 these tubes, I shall be extremely obliged. 



