224 BULLETIN OF THE BUREAU OF FISHERIES. 
millimeters, respectively. There is, however, a considerable range of variation 
in size, particularly in the second and third stages, and there is good evidence 
that in general the larger specimens are the better fed. For this reason the 
average size of the lobsters of the various stages in particular rearing experi- 
ments forms, perhaps, a basis for judging whether the lobsters are doing well 
or not. 
The length of the combined larval stages varies greatly and is directly and 
powerfully influenced by the temperature and food. It ranges from nine to 
FiG. 3.—Third stage. 
4 
LARVAL LOBSTERS, LATERAL VIEW. 
more than twenty-five days (twenty-one days is extremely long at Wickford). 
From the viewpoint of practical culture, the length of the total larval period is 
of very great importance, though the duration of the first, second, and third 
stages severally does not seem to be so. 
DIFFICULTIES IN REARING. 
In artificial culture, of course, the fry must be confined in large numbers, 
and it is practically impossible to separate them from one another. Therein 
appears an initial difficulty which all experimenters have had immediately 
thrust upon them. ‘The fry, under these circumstances, at once exhibit a most 
