r>44. CKESSWELl, STIEAIJEU ANT> POItOTllY .TOltDAN LLOYD, 
Tlio blastulie obtained by this combined metliod are very 
liealthy. Tliey swim up to tiie top of the culture vessel 
within 18 hours, and up to the eig-ht-armed pluteus stage grow 
more rapidly than normally fertilised eggs. 
Given in detail the method consists in treatingr the e<z£CS 
with — 
(1) 3 c.c. N/10 butyric acid + 50 c.c. sea-water for I'O 
minutes. 
(2) Wash in two or three changes of sea-water. Transfer 
to — 
(3) 10 c.c. sea-water + 40 c.c. T13 M sucrose solution + T4 
c.c. M/60 tannic acid for G minutes. 
(4) T5 c.c. N/10 ammonia is added to (3) for 1 hour. 
(5) Wash in three or four changes of sea-water, transfer 
to — 
(6) Normal sea-water. 
We have been imsnccessful, however, in bringing any of 
the larvae obtained by this method through metamorphosis, 
despite the fact that they at first grew considerably faster 
than the normal sperm-fertilised ones. Their rapid rate of 
growth at first is remarkable, as the plutei obtained by this 
method liave frequently attained the eight-armed condition in 
half the time that it takes the normal larva; to reach this stage, 
d'heir development becomes, however, very slow after this, and 
only a few lived to develop an Echinus-rudiment. 
'I'he great objection to this method, and the probable l eason 
why the larvae obtained by it die off so rapidly in the late 
stages, is due to the difficulty of getting rid of all traces of 
the chemical solutions with which the eggs have been treated. 
When the eggs are transferred finally to normal sea-water, 
this in a few days’ time, despite repeated washings, invariably 
goes cloudy and the larvae seem to be killed. In some cases 
we washed the eggs in as many as thirty or forty changes of 
sea-water, and still the whole jar went cloudy in the course of 
a few days. We had recourse to pipetting off a few larva; and 
placing them in a separate jar, as the only successful way of over- 
coming this difficidty. We were, however, unable to get any 
