THE MALPIGHIAN BODIES. 493 



there is a complete segmental tube (s. t} which opens at its 

 upper extremity into an irregular vesicle, prolonged behind into 

 a body which is obviously a developing Malpighian body, m.g, 

 and in front into a wide tube cut obliquely in the section and 

 ending apparently blindly (p.x]. In the preceding segment 

 there is also a segmental tube (s. t] whose opening into the body- 

 cavity passes out of the plane of the section, but which is again 

 connected with a vesicle dilating behind into a Malpighian 

 body (m.g) and in front into the irregular tube (p.x), as in the 

 succeeding segment, but this tube is now connected (and this 

 could be still more completely seen in the segment in front of 

 this) ivitJi a vesicle wJticJi opens into the thick-walled collecting 

 tnbc (fourth division} of the preceding segment close to the 

 opening of the latter into the Wolffian duct. The fact that the 

 anterior prolongation of the vesicle ends blindly in the hinder- 

 most segment is due of course to its terminal part passing out 

 of the plane of the section. Thus we have established between 

 stages O and P a connection betiveen each segmental tube and 

 the collecting tube of the segment in front of that to which it 

 properly belongs ; and it further appears that in consequence of 

 this each segment of the kidney contains two distinct coils of 

 tubnli 'cvliicli only unite close to their common opening into the 

 Wolffian duct! 



This remarkable connection is not without morphological 

 interest, but I am unfortunately only able to give in a frag- 

 mentary manner its further history. During the greater part of 

 embryonic life a large amount of interstitial tissue is present in 

 the embryonic kidneys, and renders them too opaque to be 

 advantageously studied as a whole ; and I have also, so far, 

 failed to prepare longitudinal sections suitable for the study of 

 this connection. It thus results that the next stage I have 

 satisfactorily investigated is that of a nearly ripe embryo 

 already spoken of in connection with the adult, and represented 

 on PI. 20, fig. 5. This figure shews that each segmental tube, 

 while distinctly connected with the Malpighian body of its own 

 segment, also sends out a branch towards the secondary Mal- 

 pighian body of the preceding segment. This branch in most 

 cases appeared to be rudimentary, and in the adult is certainly 

 not represented by more than a fibrous band, but I fancy that I 



