418 Mil. H. M. BEE]S^AED O'S THE CHEENETID^. 



three pairs, and Daday four pairs in the cylindrical part of the 

 dorsal vessel, and, in addition, four extra openings in a rosette- 

 like terminal portion. 



In a series of transverse sections, I found that in the dorsal 

 median line above the hind-gut {cf. figs. 6 and 7) there existed a 

 blood-sinus full of coagulum, but without any trace of a dorsal 

 vessel. The heart or dorsal vessel commenced (working froai 

 behind forward) where the hind-gut joined the mid-gut. I 

 should therefore be inclined to think that there could be only 

 one pair of ostia in the abdomen. Whether there are any in the 

 cephalothorax I was unable to ascertain. 



A cross section of the expanded heart might almost be 

 mistaken for that of Scorpio. There is even a pair of fibrous 

 bundles attached to the ventral surface, and drawing down the 

 pericardium into the long conical processes which we find in 

 Scorpio, the muscular attachments of which have been called by 

 Lankester * the veno-pericardial muscles. 



The blood collected by the heart from the median dorsal sinus 

 and the pericardium is driven forward through the coils of the 

 spinning-glands ; after circulating in the anterior regions of the 

 body, it returns along the ventral surface, finding its way to the 

 heart again through the constrictions {m.d., figs. 6 and 8) of the 

 diverticula formed by the dorso-ventral muscles and in the 

 median plane between the mid-gut diverticula, bathing the hind- 

 gut on its way into the median dorsal sinus. 



In the pathological specimen (p. 416), the globular nests of 

 bacteria are found chiefly in the walls of the passages formed 

 by the dorso-ventral muscles which were enormously stretched 

 by coagulated blood (fig. 8). 



The spinning-glands were always supposed to be near the 

 genital aperture, where also, according to Stacker, they occur in 

 the related (?) form Gihhocelhim. The important discovery by 

 Groneberg, that they are really in the cephalothorax and emerge 

 behind the tip of the movable joint of the mandibles, I have been 

 able fully to confirm. At the same time, the view of the older 

 zoologists was not altogether wrong ; there are glands which 



* Lankester and Beck, Trans. Zool. Soc. vol. xi. pt. 10. 



