THE AMERICAN LOBSTER. 
41 
SUMMER EGGS IN VINEYARD SOUND. 
The following tables illustrate the time of spawning of the lobster in the vicinity 
of Woods Hole, in Vineyard Sound, and about Gay Head. The date of the extrusion 
of the eggs is, of course, only approximately determinable. It is estimated from obser- 
vations on the rate of development of embryos at Woods Hole. The parent lobsters 
were confined in floating latticed boxes, which were exposed to the wash of the waves, 
in one instance, for nearly a year. (See table 18, p. 56.) 
Table 3. — Time of spawning of the lobster in Vineyard Sound and vicinity in 1889. 
No. 
Locality. 
Date of 
capture. 
1 
Woods Hole Harbor.. 
July 10 
2 
Menemslia 
July 11 
3 
...do .... 
4 
.. .do 
5 
6 
.. .do .... 
7 
8 
...do 
9 
10 
11 
12 
13 
July 16 
14 
...do 
. . .do 
do 
...do .... 
16 
17 
July 18 
18 
do 
July 20 
19 
20 
do 
Stage of development. 
Thoracic abdominal plate well marked . . . 
At least four pairs of appendages behind 
mandibles. 
Eggnauplius: second antennae bilobed.. 
do 
do 
Close of yolk segmentation 
Yolk segmentation : 60 to 100 segments. . . 
do 
do 
do 
do 
Early egg nauplius : second antenna) not 
bilobed. 
Eggnauplius, later stage: second anten 
use bilobed. 
Close of yolk segmentation 
Thoracic abdominal plate becoming prom- 
inent. 
Yolk segmentation: 50 to 100 segments- .. 
Large thoracic abdominal plate. Pit ob- 
scured. 
Very slight invagination : nuclei close to 
surface. 
Eye pigment developed 
do 
Age of embryo. 
8 to 9 day s . . . 
20 to 21 days . 
14 to 15 days. 
do 
do 
3 days 
R days 
. .... do 
do 
do 
do 
10 days 
14 to 15 days . . . 
3 days . 
6 days . 
1J days 
8 to 9 days. . 
4 days 
27 days . 
. . . do . . 
Date of 
extrusion 
of eggs. 
July 1 
June 20 
June 26 
Do. 
Do. 
J uly 8 
July 9 
Du. 
Do. 
Do. 
Do. 
July 1 
Do. 
July 13 
July 10 
July 14 
July 9 
July 16 
July 
July 
Table 4. — Time of spawning of the lobster in Vineyard Sound and vicinity in 1890. 
No. 
1 
2 
3,4 
5 
6-14 
15-17 
18 
19 
20 
21-26 
27-45 
46-51 
52, 53 
54 
55 
56-60 
61 
62 
63 
64 
65 
66-68 
69, 70 
71-73 
74 
75 
76, 77 
78-81 
82-84 
85,86 
Locality. 
Date of 
capture. 
July 7 
July 9 
July 28 
do 
do 
do 
July 30 
July 30, 
1.45 p.m. 
July 30 
. .do 
...do .... 
do 
do 
do 
Aug. 1 
...do .... 
.. .do 
...do .... 
Woods Hole Harbor. . . 
Aug. 5 
Aug. 11 
.. .do 
...do .... 
.. .do 
Woods Hole Harbor. . . 
Aug. 14 
do 
Aug. 18 
Aug. 20 
.. .do 
Aug. 21 
Stage of development 
Yolk segmentation probably not begun. 
Yolk unsegmented 
Post-nauplius stage 
Eye pigment just visible 
Close of yolk segmentation 
Invagination stage, small pit 
Yolk segmentation : 16 to 60 segments. . . 
Yolk unsegmented 
do 
Early segmentation of yolk. 
Close of yolk segmentation. 
Invagination stage 
Egg nauplius 
Eye pigment formed 
Egg nauplius. 
Age of embryo. 
Close of yolk segmentation 3 days 
XT ,.11, „4-„4-; — . . Id 4-„ ..4-.-. .-n j. 
24 hours 
Eew hours 
21 days 
27 days 
3 days 
4 to 5 days 
24 to 30 hours. - 
A few hours . . . 
About 8 hours - 
24 to 30 hours . . 
3 days 
5 days 
15 days 
27 days 
15 days 
Yolk segmentation: 16 to 60 segments . . 
Thoracic abdominal plate formed 
Invagination 
Egg nauplius 
Eye pigment formed 
Invagination 
Thoracic abdominal plate formed 
Egg nauplius 
Invagination 
Post-nauplius stage 
Invagination (?) 
Egg nauplius 
Post-nauplius stage 
Early egg nauplius 
24 to 30 hours. . . 
8 to 9 days 
5 days 
15 days 
27 days 
5 days 
8 to 9 days 
15 days 
5 days 
20 days 
5 days 
15 days 
21 days 
10 days 
Date of 
extrusion 
of eggs. 
July 6 
J uly 9 
J uly 7 
J uly 1 
July 25 
July 24 
July 27 
Julv 30 
Do. 
July 29 
July 27 
July 25 
July 15 
J illy 3 
July 17 
July 29 
July 31 
July 23 
July 31 
July 27 
July 15 
Aug. 6 
Aug. 2 
July 27 
Aug. 9 
July 25 
Aug. 13? 
Aug. 5 
July 31 
Aug. 11 
