488 EDWIN S. GOODRICH. 



directly continuous with capillaries coming from the 

 intermediate intermuscular plexus, and this network 

 amongst the muscles passes on its inner side into 

 larger channels, which are, in fact, offshoots from the 

 lateral branches of the dorsal sinus (figs. 7 — 11). 



The epidermal network may, therefore, be considered as the 

 region where the sinus system opens into the contractile vas- 

 cular system. In figs. 8 — 11 three consecutive sections and 

 a reconstruction of the same are drawn, showing this connec- 

 tion in a small portion of the region represented in fig. 7. A 

 similar continuity can, of course, be found throughout the 

 other parts. 



There can be no doubt whatever that the dorsal sinus com- 

 municates with the lateral vessels by means of small branches 

 given off by each system to the superficial plexus. Indeed, 

 the distribution of the radial capillaries going to the skin 

 being what it is (figs. 7 and 12), it is evident that such a 

 connection must exist; the blood brought by one set of 

 capillaries must necessarily be carried off by the other. Once 

 the disposition of these small channels was ascertained, their 

 continuity was a foregone conclusion. But, of course, it 

 is satisfactory, and necessary for the sake of dispelling all 

 doubt, to have the actual evidence of sections before us. 



The communication of the contractile system with the ven- 

 tral sinus must now be established. 



A reconstruction of a portion of the capillary system of the 

 ventral region is given in fig. 12. It will be seen at once that, 

 although the actual disposition of the capillaries is quite 

 similar to that described in the dorsal region, yet the conditions 

 are reversed. For here the annular channel comes directly 

 from the ventral sinus (cp. figs. 7 and 12), and the radial 

 capillaries derive from the contractile system, being branches 

 of the latero-abdominal vessel. 



A small portion of the region represented in fig. 12 has been 

 reconstructed, so as to be shown on a larger scale in fig. 13. 

 Here the continuity between the two systems is again 

 proved. 



