W. H. FURLONGE ON THE TULEX IRRITANS. 21 



is accomplished — the air is forced throiigli the infinitely less than 

 capillary ultimate fibrils of the trache£e, and in this opinion Mr. 

 Lowne coincides. 



I am now brought to a few suggestive remarks which I desire to 

 offer upon the functions of the wonderful respiratory apparatus 

 just described, as a whole. 



The problem to be solved is, in what way does this apparatus act 

 in maintaining a constant and regular circulation of air through 

 every tube and fibril of the air system ? It has been suggested that 

 inspiration is accomplished by the dilation of the abdomen by 

 voluntary muscular action, and conversely, that expiration is 

 effected by corresponding muscular compression. But I would 

 ask, is it by any means an ascertained fact that the air in- 

 spired through the abdominal spiracles is expired through the 

 same orifices ? I cannot venture to assert positively that it is 

 otherwise, but I strongly incline to susjDect the probability that the 

 air inspired through the abdominal spiracles may be expired through 

 the spiracles of the thorax. The appearance and apparent action 

 of the so-called erectile spiracles of the thorax seems, to my mind, 

 to lend support to the idea, and it is from these considerations I 

 have been led to suppose that similar spiracles will probably be 

 found to exist in the other segments of the thorax. 



I put these views forward as jourely suggestive, and with the 

 hope of promoting enquiry and work, in a most important and in- 

 teresting department of insect structure, upon which, I believe, our 

 knowledge at the present time is very limited ; and I cannot help 

 thinking that a collation of the knowledge possessed and a com- 

 parison of the opinions entertained by individual members of our 

 Club could not fail to throw much light upon the subject. I shall 

 be very glad if the expression of these hypothetical views has the 

 effect of inducing such a discussion, even should the result be (as 

 is, indeed, very likely) to demolish the conjectures I have formed. 

 May I be permitted to say that discussions of this character, con- 

 ducted in the spirit of simple investigation and search for truth 

 amongst our members, would infallibly result most beneficially to 

 the progress of knowledge in those branches of science which we 

 are incorporated for the express purpose of promoting. 



The Beproductive System. — The structure of the reproductive 

 organs of the female flea is comparatively simple ; that of the 

 male is exceedingly complex and remarkable. 



