140 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



that it has the same action on polarized light as chitin ; * 

 and as it is insoluble in cold 30% caustic potash, or when 

 warmed in 25% caustic potash to 130° F., while it swells 

 up with strong HC1, it is safe to conclude, not indeed that 

 it is identical with chitin, but at any rate that it is of a 

 similar nature.! 



With regard to the development of the bow-shaped 

 corpuscle I can say nothing certain. I have noticed in 

 the haemolpnph, however, small corpuscles similar to the 

 amoeboid kind described by Eisig, but differing from them 

 in being of a fusiform shape and in containing a short, 

 straight, colourless rod (fig. 1). It is possible that these 

 are the forerunners of the bow-shaped corpuscles. On 

 the other hand, it is to be noticed that as a rule the 

 smaller the corpuscle the greater the curve of the bow. 



Having now described this curious body, it may be 

 asked, "But is it a corpuscle at all?" I confess that 

 when I first met it in a film of haemolymph, I regarded 

 it merely as a parasite. Finding that the organisms 

 occurred in other films however, and that by searching 

 they could always be found scattered about in any film of 

 hseniolyruph, one was more and more impressed with 

 the possibility of their being true corpuscles. No gre- 

 garine or other unicellular parasite is known, so far as I 

 am aware, which resembles such a structure. That the 

 rods might be setae of the worm engulphed by a leucocyte 

 is highly unlikely. When setae are found in the coelom 

 of worms, as is commonly the case, they are engulphed 

 by a plasmodium formed of numbers of leucocytes, whereas 

 the bow-cells have never more than one nucleus. Again, 



* I have to thank Prof. Paul Mayer, of the Zoological Station at Naples, 

 for pointing this out. 



t Dr. Gustav Mann noticed that the rod seems to be transversely flattened 

 on its concave side. 



