Biochemistry and Evolution 57 



arginine in many marine invertebrates, leading to glycoevamine in 

 some annelids and thence on to creatine in other annelid species. 

 Perhaps the time has come to reexamine the echinoderms and proto- 

 chordates in case this intermediate stage has been preserved for 11- 

 there too. 



The discovery of tanrocyamine was interesting inasmuch as trans- 

 amidination is a fairly rare event. Longest known is the transfer of 

 the amidine group from arginine to glycine, yielding glycoeyamine. 

 It seems likely that tanrocyamine arises by a similar transfer from 

 arginine to taurine, for taurine is widely distributed in the animal 

 kingdom and occurs in remarkably large; quantities in certain mol- 

 lusks, e.g., Abalone (Schmidt and Watson, 1918) and. more interest- 

 ing, in at any rate some annelid worms (Kurtz and buck, 1 935 I. So, 

 discoveries of this comparative kind can sometimes add something to 

 the vast and ever-growing body of general biochemistry. Another 

 example that comes to mind is the discovery of octopine in cephalo- 

 pod mollusks ( Morizawa, 1927) and in some lamellibranchs and gas- 

 tropods ( Irvin and Wilson, 1939). This substance appeared to give 

 promise of restriction to certain fairly sharply defined groups of ani- 

 mals, but later turned out to be very closely allied to the intermediate 

 compounds formed in the probably universal process of transamina- 

 tion. 



As time goes on, then, more and more of the supposedly secondary 

 and specific features of particular groups or species tend to become 

 incorporated into some more general plan, and examples could be 

 multiplied considerably. It may well be, indeed, that as comparative 

 biochemistry becomes more comparative, more and more of the odd. 

 peculiar, and apparently restricted phenomena known today will 

 prove to he widely and in some instances perhaps even universally 

 distributed, perhaps even as parts of the fundamental metabolic 

 ground plan. Even the production of large amounts of steam-volatile 

 fatty acids by parasitic worms I Ascaris lumbricoides) (Moyle and 

 Baldwin, 1952 I. long thought to be unique, at leasl among animals, 

 finds a close parallel in the production of similar acid- b\ the action 

 of ruminant symbionts upon cellulose (McAnally and Phillipson, 

 1944), but this does not seem by any means a widespread or funda- 

 mental phenomenon. 



At this stage two general comments may be made: first, thai we arc 

 inclined to study too few species and are tempted to draw too far- 

 reaching conclusions from too little evidence. For this we have to 

 blame sometimes ourselves, sometimes shortage of funds, and some- 

 times the weather, especially at marine station-. Secondly, and thi- 



