532 CRESSWELL SHEARER AND DOROTHY JORDAN LLOYD. 
experimeuts, in the two years. If possible, a higher per- 
centage of blastnlte was obtained during 1912 than in the 
previous yeai-. They seemed healthy and vigorous in every 
way, but did not survive to metamorphose as did those of the 
previous season. 
II. Loeb’s MgCh Method and Delage’s HCl Method. 
Some preliminary experiments were tried with a few of 
the early metliods that have been devised by Loeb ( 11 ) and 
Delage (3 and 5) for producing artificial parthenogenesis, with 
a view to finding out what results they would give with eggs 
at Plymouth. 
A large percentage of eggs were successfully induced to 
segment somewhat irregularly with Loeb’s MgClo method. 
In all cases the segmentation was highly irregular even in the 
first stages, and became progressively more irregular as 
cleavage advanced. A small percentage of the eggs ulti- 
mately developed into unhealthy-looking prism larvae, and 
finally into very abnormal plutei (figs. 3 and 5). 
The most satisfactory results were obtained by placing the- 
eggs in the following solution : 
50 c.c. 20/8 N MgCL -)- 50 c.c. sea-water 
for two hours, and then transferring them back to normal sea- 
water. About 5 per cent, of the eggs formed plutei. In all 
these cases plutei were very unhealthy, and at the end of four 
days had become highly abnormal (figs. 3 and 5), although 
some lived for a fortnight or more, by the end of which time 
they had degenerated into shapeless masses of cytoplasm. 
Some very irregular blastulge were also obtained by 
Delage’s (3) HCl method, but these never progressed beyond 
the blastula stage. 
As both the above methods g’ave little promise of being 
much use for our work, they were not carried beyond the- 
preliminary stage, and were soon abandoned. 
