402 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
in ascidians, echinodermata or worms, which have 
similar food matters. 
The nature of the style is decidedly not that of a 
reserve food material, and it seems difficult to comprehend 
why, under normal conditions, marine lamellbranchs 
should require to make provision for times of starvation. 
Barrois, who rejects the theory of reserve food 
material, states that he was never able to detect a 
diminution in the styles at various seasons nor even after 
keeping specimens cf Cardium in filtered water for some 
days. Both Mitra’s experiments and my own confirm 
Hazay and Haseloff (24 and 25) as far as this is concerned, 
and the chief objection to the reserve food stuff theory 
must be the composition of the style itself. The position 
of the style and its composition tell strongly against the 
theory of it being an excretion. When the animal is 
kept under such conditions as deseribed by Mitra, is it 
absorbed by the animal or simply dissolved away by 
water passing through the alimentary canal? Possibly 
it 1s absorbed and the ferment used for converting the 
glycogen (which is stored up in large quantities in most 
lamellibranchs) into sugar. 
The development of a caecum certainly points to a 
storage for some purpose. ‘There is no doubt that in 
Pecten, where the style seems to occupy the whole area 
of the intestine, it hinders the food from passing too 
quickly through the alimentary canal, and provides an 
additional surface over which its contained amylolytic 
ferment can act. It must be remembered, however, that 
the presence of this ferment in the style is not conclusive 
proof that the style has been evolved as a ferment or 
method for storing a ferment. 
It has been already stated that the last portion of 
the intestine passes through the pericardium and the 
