large (the fresh water Peotinatella nagnifioa may cover several square 
feet in the course of a siimmer). 
All of your specimens from crabs are probably of this 
season’s growth and the only one that shows age is the large circular 
one, Lichenopora hispida (Fleming), from the Tondeleyo crab trap# 
Several other specimens, as noted, are in reproduction, but in some 
species this may happen in a few weeks time, as I have noted at Woods 
Hole and at the Tortugas. It would be a good problem for some one to 
follow up. 
Possibly you can get more information on the rate of develop- 
ment of barnacles as they have been more studied in relation to the 
fouling of ship bottoms. Dr. J. P. Visscher, Dept. Biology, Western 
Reserve Univ. , Cleveland, might be able to furnish some information, 
as he has studied the rate of fouling on both coasts and at Hawaii. 
The little white circles you mention are Lichenopora (both 
species listed above). As all but one colony are juvenile they must 
be of the present summer at least. Even the one in reproduction looks 
young. They seldom grow more than a quarter of an inch across. 
• # • • 
Raymond G. Osborn 
