142 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



brown colour; darker in the middle than at the ends, 

 whilst the ends are broader than the middle ; notched ; 

 and often forked. The rods are contained in single 

 cells of colourless protoplasm, with a nucleus lying in 

 a slight depression in the middle of the rod. The pro- 

 toplasm extends as a very attenuated layer over the 

 ends of the rods, and in the middle region sends out 

 filamentous, slowly waving processes. A few granules 

 and vacuoles occur in the cell substance. Schaeppi gives 

 an excellent account of the formation of the rods by 

 several green granules in a cell fusing in one alignment, 

 and of their growth at the ends, w T here the tension of the 

 protoplasm is obviously greater than at the centre, 

 entailing the deposition of the fresh granules on the 

 extremities. He shows that the substance of which the 

 rods are formed is certainly chitin, and regards it as being 

 derived from the nucleus of the corpuscle. The function 

 of the corpuscle, he considers, to be excretory. With 

 the exception of the two last points, the account is 

 excellent ; but that excretion is the function of the 

 corpuscles, whilst the only substances which they are to 

 excrete are the degeneration products of the nucleus of 

 the cell, seems to me impossible. If every other nucleus 

 in the body had such provision for its excretion, the 

 result can hardly be imagined. Be that as it may, 

 Schaeppi ? s account leaves no doubt that the rod-cells of 

 Ophelia are corpuscles. 



No other rod containing corpuscles have been described 

 throughout the animal kingdom, so far as I am aware ; 

 but, on the other hand, it is the commonest thing to find 

 deutoplastic products in blood and coelomic corpuscles. 

 Some of these are of a very remarkable nature, and, 

 though differing in form, may have a similar raison d'etre 

 to the bow-cells. I may take an instance from Oligochaeta 



