SURVEY OF INVERTEBRATES 93 



able to the bottom organisms. But the amounts of oxy- 

 gen that could be obtained in this manner are obviously 

 extremely small and would likely be used up by the rich 

 bacterial flora of the mud before the much bulkier bot- 

 tom metazoa could obtain any significant quantity. 



Another possibility was that the lamellibranchs "have 

 a store of available oxygen in their tissue which suffices 

 to supply the necessary oxygen when the outside supply 

 is cut off " (Collip, 1921). Searching for such a source, 

 Berkeley (1923) was the first to point out that in the 

 crystalline style of Saxidomus giganteus a compound oc- 

 curs that oxidizes guaiacum, but not paraphenylenedia- 

 mine or pyrogallol, in the absence of hydrogen peroxide 

 or air, and that is not destroyed by boiling. Berkeley 

 {I.e.) expressed the opinion "that the substance con- 

 sists of a complex of an oxidizing agent and an enzyme, 

 the enzyme being capable of conveying oxygen from the 

 oxidizing agent to the body oxidized. It would thus re- 

 semble an oxidase except that its activity would be limit- 

 ed by the amount of oxygen available for transfer from 

 the non-enzyme component." Similar enzyme complexes 

 have been found in the crystalline style of many lamelli- 

 branchs, but also in other organs, for example, the gills 

 (Cole, 1921 ; Berkeley, 1933a, 1935; Yonge, 1926; Graham, 

 1931). A detailed discussion of the various enzymes in- 

 volved is presented by Berkeley (1933). One of the 

 main arguments brought forward by him (1923) to 

 support his view of the importance of this system for 

 anaerobic life as a "store of fixed oxygen" was that the 

 crystalline style disappears rapidly if the animals are 

 kept under anaerobic conditions, an observation confirmed 

 byNozawa (1929). 



There can be no question about the reality of this en- 

 zyme complex, but it is doubtful whether it has the sig- 

 nificance attributed to it by Berkeley, There is, first of 

 all, the curious point that, though the crystalline style 

 seems to disappear very rapidly in the absence of oxygen, 



