602 DE. H. CHARLTON BASTIAN ON THE ANATOMY AND PHYSIOLOGY 



contact with one another. If this were their principal oflBce, we can imagine that it 

 might be, to a certain extent, immaterial whether the connecting vessels traversed the 

 left or the right half of the body, or were distributed unequally on the two sides. Then 

 comes the puzzling question, what can be the use of vessels to establish a communication 

 between what appear to be two solid cords 1 And in reply I can only again refer to 

 the impression which I have frequently been inclined to adopt, that in some species the 

 median lines are traversed by a lacunar canal, and at the same time deplore the diffi- 

 culties besetting the solution of this question. Schneider states that these vessels have 

 a reddish colour in A. megalocephala ; this I suppose must have been seen in the fresh 

 animals before immersion in spirits of vnne, in which condition, owing to their poisonous 

 effects upon me, I have never been able to examine them. The colour was in all pro- 

 bability due to the fluid contained within the vessels. I-have looked for similar trans- 

 verse vessels in many Ncmatoids, but have only found them in the two above named. 

 ScHXEiDER, however, states that he has discovered them in HeteraMs vesicularis, and 

 many other minute Nematoids, though he has failed to recognize them in any species of 

 the genera Oxyuris or Strongylus. Further investigation, both with regard to the con- 

 nexions of these vessels, and to their prevalence amongst the Nematoids generally, would 

 be most desirable. 



THE EESPIRATORY FUNCTION— HOW PERFORMED? 



Amongst the lower Invertebrata it is a well-known fact that the function of respiration 

 is effected by the most dissimilar means, and often by distinct processes working inde- 

 pendently in the same animal towards the fulfilment of a similar end. We need not 

 be surprised therefore if such is found to be the case amongst the Nematoids. It is, 

 however, rather remarkable that cilia, which often (as first pointed out by Dr. Shakpet *) 

 play so important a part in the respiratory processes of the invertebrate animals, should 

 never yet have been detected in any Nematoid either parasitic or free. 



The function of respiration seems to be duplicate in its nature: one object which it 

 fulfils in the animal economy being to secure a certain amount of oxidation of the 

 tissues, and the other being the performance of a function of elimination, supplemental 

 in its nature to the similar work effected by the two other great excretory organs, the 

 kidneys and liver f. It may well be that the relative proportions of these two processes 

 in different animals may be variable, since a greater activity of the eliminatory function 

 — performed by organs howsoever named — might atone for an inefficient accomplish- 

 ment of the process of oxidation. In many of the pai-asitic Nematoids, we can well 



* Cycl. of Anat. and Pliys. vol. i. Art. Cilia. 



t Even, tliis process of oxidation appears to be in great part destined to perform a disinteg^ting fanction, 

 and so may perhaps be looked upon as the first stage of a process of elimination. Dr. Liokel Beaxe says, 

 " Oxidation seems to be connected rather with the disintegration or removal of fully developed and worn-out 

 tissue than with the growth and multiplication of masses of germinal matter." — On Injlamtnation, Med. Times, 

 1865, vol. i. p. 594. 



