138 TEANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



combined fluid of blood and lymph, Eisig has proposed 

 the name " Haemolymph," as indicating the two sources 

 of its origin and the double function it performs. Both 

 in Arthropoda and in certain Polychaeta, then, a combined 

 fluid is formed, though by two entirely different processes, 

 which represents blood and perivisceral lymph, fluids 

 which are separate in vertebrata and in the majority of 

 Chaetopod worms. 



There is an astonishing variety in the corpuscles in the 

 body -fluids of different worms. Species very closely allied 

 may show extraordinary differences in this respect. 



It is hopeless, at present, to attempt to be compre- 

 hensive ; in such an untrodden country, we may pass 

 straight to one point of interest, a certain peculiar 

 corpuscle which I came across in the haemolymph of 

 Notomastus profundus, a Capitellid worm. After describ- 

 ing it I shall endeavour to compare it with the corpuscles 

 of other worms, which will be incidently described. 



The worm is common in certain beds of sea-weed in the 

 Bay of Naples. It is of a reddish colour and about two 

 inches long. An excellent description of the corpuscles 

 of the haemolymph is to be found in Eisig' s monograph 

 on the group. He recognises two kinds, small, colourless 

 amoeboid leucocytes, and large flattened disc-shaped cor- 

 puscles, which are of a yellow colour due to haemoglobin, 

 the latter are nucleated, and contain large brown chitinous 

 concretions, which show a concentric marking. Eisig 

 thinks that the concretions represent degeneration stages 

 of haemoglobin. 



Besides these two kinds of corpuscles, I have found a 

 third (figs. 3 and 4) occurring in relatively much smaller 

 numbers than the others, but, nevertheless, present h 

 every specimen of the haemolymph which I have examined. 

 It varies considerably in size, but frequently reaches a 



