Giant nerve fibers in annelids

Geoff Read at
Fri Mar 29 16:44:32 EST 2002

James Mahaffy,
> I ran across information in the second edition (1977) of Edwards and
> Lofty's Biology of earthworms (p. 105) that I think may be a typo. 
> They say that giant nerve fibers in annelids (I assume Lumbricus 
> terrestris) transmit impulses at 600 meters per second. 

In Stephenson (1930) "The Oligochaeta" the rate is given as 1.5 metres 
per second for earthworms. In Barrington (1967) "Invertebrate structure 
& function" the earthworm rate is 17 to 25 m/sec for the median giant 
fibre. Laverack (1963) "The physiology of earthworms" has the same 
figure and gives three journal sources for the original works done in the 
1930's - 40's.  

The annelid speed king is more likely to be a polychaete, being altogether 
rather more quick-witted and alert creatures that like to get out of the way 
before being chomped, but I do not have anything to hand that will tell us 
whether 600 m/s is conceivable and not a lapsus as one might suspect.    

Geoff Read < at>

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