92 THURLOW C. NELSON. 



the style in this mollusc, and that the absence of spirochsetes in 

 many molluscs is due to the very firm and resistant styles which 

 they possess. 



Although the solidity and resistance to dissolution of the style 

 may effect the distribution of Cristispira, they are certainly not 

 the most important factors. As Nogouchi himself admits, and as 

 Edmondson showed, the style of My a is very firm and relatively 

 resistant to dissolution, yet it harbors Cristispira in an abundance 

 second only to that of Ostrea. 



Martin ('23), studying the relative importance of the net 

 plankton and of nannoplankton in the food of the oyster, found 

 that water from which even the smallest nannoplankton organ- 

 isms including bacteria had been removed would, if well aerated, 

 permit reformation of the style in Ostrea. He concluded that 

 although the appearance of the style in this mollusc is usually 

 correlated with the taking in of food, this structure may arise in 

 the complete absence of food, presumably as a response to the act 

 of siphoning. 1 



Three months after the publication of Martin's paper appeared 

 an interesting communication from Berkeley ('23) regarding the 

 function of the crystalline style as a possible factor in the 

 anaerobic respiration of certain marine molluscs. This investi- 

 gator attempts to account for the continued production of carbon 

 dioxide by marine molluscs kept under anaerobic conditions, as 

 demonstrated by Collip ('21). In seeking a possible explanation 

 of this production of carbon dioxide Berkeley tested the reactions 

 of various tissues and of the style of Saxidomus with an alcoholic 

 solution of gum guaiacum. Only in the case of the style did he 

 obtain a deep blue color, which suggested to him that this 

 structure might be associated with anaerobic respiration. Mol- 

 luscs kept under anaerobic conditions showed in all cases an 

 absence of the style. In an earlier paper (Berkeley, '21) it was 

 shown that a disappearance of glycogen accompanies anaerobiosis 

 in Saxidomus gigantea, though not in Paphia nor in Mya. 



It is pointed out in a footnote of Berkeley's ('23) paper that the 

 work was done in ignorance of the publications of Mitra, Allen, 



1 Although an oyster has no siphons, this term has come into such general use for 

 the process of passing water through the gills of a mollusc that it seems best to 

 employ it here especially as no good substitute appears to be available. 



