THE BEE. 57 



the spinal chord, with its nervous ganglionic .centres, 

 will be found to traverse the dorsal region of the 

 body: they run, in fact, along the bach, whilst the 

 heart is situated in front ; but in the Bee the central 

 nervous chord passes along the ventral portion, whilst 

 the tubular heart occupies a place immediately within 

 the integument of the dorsal surface. The circu- 

 lating apparatus consists chiefly, so far as anatomists 

 have hitherto been able to trace it, of what is called 

 the dorsal vessel (ia consequence of its running along 

 the back of the body). This dorsal vessel assumes 

 the form of a tube, attached to the outer integument 

 by bands or ligaments, and that portion of it which 

 is situated ia the abdomen is divided into eight 

 chambers, communicating with one another by means 

 of valves so constructed as to admit of the blood 

 passing ia one direction only, that is to say, towards 

 the head. After it has traversed the abdominal 

 chambers, which may be compared to the chambers 

 of our heart, the sanguineous fluid continues its course 

 through the thorax, where the dorsal vessel forms a 

 simple contractile tube (the aorta) without any di- 

 visions, and thence it is forced into the head and 

 other parts of the body. 



The circulation of the Bee cannot, however, be 

 completely traced, nor is it, so far as we are able to 

 judge, of a perfect character ; for, although it has been 

 stated by some anatomists that a portion of the blood 

 is conducted back from the head to the posterior 

 part of the body by means of a smaller tube situated 



D 5 



