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. 50.) 



Table 3. — Time of spawning of the lobster in Vineyard Sound and vicinity in 1S8U. 



No. 



3 

 4 

 5 

 6 



7 

 8 

 9 

 10 

 U 

 12 



13 



14 

 15 



1G 

 17 



18 



19 

 20 



Locality. 



Woods Hole Harbor. 

 Menemsha 



.do . 

 do 



Woods Hole Harbor.. 



....do 



Menemsha 



do 



do 



Woods Hole Harbor.. 



do 



do 



Date of 

 capture. 



Stage of development, 



July 10 

 J nly 11 



.do. 

 .do. 

 do. 

 .do. 

 .do. 

 .do. 

 .do. 

 .do. 

 .do. 

 .do. 



Age of embryo. 



do July 16 



do I 



Thoracic abdominal plate well marked ... 8 to 9 days. 



At least four pail sof appendages behind 20 to 21 days. 



mandibles. 



Egg nauplius : second antenna; bilobed.. 14 to 15 days. 



.do 

 do 



.do 

 do 



.do. 



.do 

 do 



do. 

 .do. 



...do.... 

 July 18 



July 20 



July 28 

 Aug. 3 



Close of yolk segmentation 



Yolk segmentation : CO to 100 segments. . . 



do 



do ... 



do 



do 



Early egg nauplius: second antenna; not 



bilobed. 

 Egg nauplius, later stage: second anten- ! 14 to 15 days. 



use bilobed. 

 Close of yolk segmentation 3 days . 



do. 

 .do. 

 3 days .. 

 1$ days . 



do .. 



do . . 



do.. 



do.. 



10 days . 



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 



days. 



1$ days 



8 "to 9' days. 



4 days . . 



27 days . 

 .. .do.. 



Date of 

 extrusion 



of eggs. 



July 1 



June 20 



June 26 



Do. 



Do. 

 July 8 

 July 9 



Do. 



Do. 



Do. 



Do. 

 July 1 



Do. 



July 13 



July 10 



July 14 



July 9 



July 16 



July 1 



July 7 



Table 4. — Time of spawning of the lohster in Vineyard Sound and vicinity in 1890. 



No. 



Locality. 



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 



7K-81 



82-84 



85,86 



-Menemsha . 



....do 



....do 



do 



....do 



....do 



....do 



....do 



....do 



...do 



....do 



....do 



....do 



do 



....do 



do 



do 



do 



Woods Hole Harbor. 

 do 



Gay Head 



...'.do 



do 



do 



Date of 

 capture. 



July 7 

 July 9 

 July 28 



. . .do 



...do ... 



...do .... 



...do ... 

 July 30 

 July 30, 

 1.45p.m. 

 July 30 



...do.... 



...do .... 



...do .... 



...do .... 

 Aug. 1 



...do— . 



...do .... 



...do .... 

 Aug. 5 

 Aug. 11 



. . .do 



...do .... 



...do .... 



...do .... 



Stage of development 



Woods Hole Harbor... I Aug. 14 



do ...do ... 



do i Aug. 18 



Menemsha [ Aug. 20 



.....do '.. .do 



do Aug. 21 



Age of embryo. 



Date of 



extrusion 



of eggs. 



Yolk segmentation probably not begun. . . I 24 hours . 



Yolk unsegmented J .Few hours. 



Post-nauplius stage 



Eye pigment just visible 



Close ot yolk segmentation 



Invagination stage, small pit 



Yolk segmentation: 16 to 60 seguients. 



Yolk unsegmented 



do 



Early segmentation of yolk 



Close of yolk segmentation 



Invagination stage 



Egg nauplius 



Eye pigment formed 



Egg nauplius 



Close of yolk segmentation 



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 



21 days . 



27 days 



3 days 



4 to 5 days 



24 to 30 hours.. 

 A few hours . .. 

 About. 8 hours . 



24 to 30 hours . . 

 ;i days 



5 days 



15 days 



27 days 



15 days 



3 days 



24 to 30 hours.. 



8 too days 



5 days 



15 days 



27 days 



5 day's 



8 to 9 days 



15 days 



5 days 



20 days 



5 daj 9 



15 days 



21 clays 



10 days 



July 

 July 9 

 July 7 

 July 1 

 July 25 

 July 24 

 July 27 

 Julv 30 

 Do. 



July 29 

 Ju!'\ 27 

 July 25 

 July 15 

 July 3 

 July 17 

 July 211 

 July 31 

 July 23 

 July 31 

 July 27 

 July 15 

 Aug. G 

 Aug. 2 

 July 27 

 Aug. 

 Julv 25 

 V. n a 13 

 Aug .'. 

 Julv 31 

 Aug. 11 



