ARTIFICIAL PARTHENOGENESIS IN ECHINUS ESCULENTUS. 535 
transferred for •75-1 hour to hypertonic sea-water (8 c.c. 
2’5 M NaCl -j- 50 c.c. sea-water), and finally to normal sea- 
water. 
Table III. 
Lot I, examined Lot II, examined Lot III, examined 
after a few hours. after 24 hours. after 24 hours. 
(1) 0-0 c.c. N/lONaOH 
-f .50 c.c. sea- water 
for 6 min. 
(2) 1 c.c. ditto 
(3) 2 c.c. ditto . 
(4) ‘3 c.c. ditto . 
(5) '4 c.c. ditto . 
. 40°/o dividing . 
in iiTegular 
manner 
. 60°/o dividing . 
. 70°/o dividing . 
. Division very . 
irregular ; 
many multi- 
polar asters 
100°/o cytolysed . 
• 3 . 5 °/g blastulaj . 50 °. ^ blastula^ 
10°/o .. • 5°/, ,. 
— • . 30°/q blastulw. 
(6) '5 c.c. ditto . . — . — . 25 °/q „ 
Note. — Lot III (4) shows how one bowl of a sei-ies may for no 
apparent reason fall greatly below the standard of the others. 
We have tried other alkalies, principally NhoCoj, as a inean.s 
of raising the alkalinit}' of the sea-water, but we have found 
NaOH the most satisfactory. Table lY gives a comparison 
of the results obtained by the use of NaOH and NiuCo.;. 
( 1 ) 
( 2 ) 
(3) 
(I) 
(5) 
( 6 ) 
(7) 
( 8 ) 
(f) 
( 10 ) 
Table IV. 
•05 c.c. N/lONaOH -p 50 c.c. 
sea- water for 6 min. 
'1 c.c. ditto .... 
"2 c.c. ditto .... 
'4 c.c. ditto .... 
I'O c.c. ditto .... 
•05 c.c. N/ 1 0 N a.YOj -f- 50 c.c. 
sea- water for 0 min. . 
•1 c.c. ditto .... 
2 c.c. ditto .... 
Lot I. 
50° /q bhistulai 
65°/o 
60", o 
50"/o 
50°/o Idastulte 
10°/o 
5°/o - 
•4 c.c. ditto .... None 
I'O c.c. ditto .... — 
Lot II. 
30°/3 Idastuhe. 
A few Ijlastula'. 
Segmentation 
very irregular. 
No division. 
