A. E. Verrill — North American Cephalopods. 
Measurements of Ommastrephes illecehrosa (in inches). 
277 
0$ 
P? 
D? 
E ? 
Ja 
ia 
R 8 
W $ 
Fresh. 
Tail to tip of dorsal arms, 
13-40 
13-00 
12-75 
10-50 
13-50 
10-50 
10-50 
8-25 
Tail to tip of second pair arms,.. 
14-20 
13-70 
14-30 
10-80 
11-10 
Tail to tip of third pair arms, 
14-20 
13-70 
13-25 
11-00 
14-20 
11-00 
11-20 
Tail to tip of fourth pair arms, _ . 
13-10 
13-60 
13-40 
10-60 
11-00 
Tail to tip of tentacular-arms, 
16-50 
17-50 
15-5 
12-00 
15-50 
12-20 
12-50 
_ _ 
Tail to base of dorsal arms _ 
10-00 
9-40 
9-00 
7-90 
10-00 
8-30 
8-20 
6-50 
8-84 
Tail to center of eve, . . 
9-30 
8-90 
8-25 
7-35 
9-50 
7-75 
7-70 
Tail to edge of mantle, above 
8-60 
8-00 
7-75 
7-10 
8-70 
7-50 
7-20 
5-70 
Tail to edge of mantle, below, 
8-20 
7-50 
7-30 
__ 
8-10 
7-15 
6-65 
5-38 
Tail to insertion of fin, 
3-30 
3-20 
3-10 
2-75 
3-50 
2-90 
2-80 
2-10 
3-44? 
Breadth of fin ... 
4-20 
4-30 
4-25 
3-78 
5-15 
3-80 
3-90 
2-65 
3-60 
Distance between lateral inser- 
tions 
■50 
•40 
•65 
•45 
Front edge, outer angle to inser- 
tion, 
2-20 
2-20 
2-00 
1-90 
2-50 
2-80 
2-10 
1-45 
Back edge, outer angle to tip of 
tail 
3-30 
3-25 
3-15 
2-90 
3-50 
3-00 
2-90 
2-00 
Circumference of body, 
4-80 
4-80 
__ 
6-50 
4-30 
400 
Breadth of body .. 
1-70 
1-60 
BB 
2-15 
1-30 
1-40 
1-10 
1-40 
Breadth of head at eyes, . ... 
1-60 
1-50 
1-35 
1-15 
1-65 
1-20 
1-30 
1-00 
Breadth of eye-opening, 
•40 
•45 
•35 
•36 
•20 
•23 
*25 
Breadth of siphon at bridle. 
•75 
•70 
•65 
•55 
■78 
•60 
•55 
Length of head, mantle to base of 
dorsal arms, 
1-40 
1-40 
1-25 
•80 
1-30 
•80 
1-00 
•80 
Length of dorsal arms, 
3-75 
3-60 
3-25 
2-70 
2-65 
2-20 
2-43 
1-75 
3-20 
Length of 2d pair, 
4-30 
4-20 
4-00 
3-15 
4-40 
2-70 
312 
2-25 
4-00 
Length of 3d pair, 
4-10 
4-25 
4-00 
3-00 
4-55 
2-67 
3-15 
2-25 
4-00 
Length of 4th pair, 
3-60 
3-80 
3-50 
2-80 
3-80 
2-43 
2-75 
2-00 
3-60 
Length of tentacular-arms, 
6-80 
8-00 
6-50 
4-00 
5-80 
4-00 
4-10 
4-50 
7-28 
Length of club, 
3-30 
3-50 
2-75 
1-85 
2-55 
1-75 
1-90 
1-30 
Breadth of dorsal arms 
•35 
•36 
•28 
•25 
•35 
•30 
.. 
•20 
Breadth of 2d pair. . 
•45 
•44 
•35 
■30 
•45 
•35 
•25 
Breadth of 3d pair 
•45 
•44 
•35 
•28 
•50 
•35 
•25 
Breadth of 4th pair, 
•44 
•42 
•32 
•30 
•45 
•35 
•25 
Breadth of tentacular-arms, 
•25 
•28 
•30 
•30 
•28 
•20 
•17 
Breadth of club, 
•30 
•30 
■22 
•18 
•25 
•22 
Front to back of 3d pair. _. 
•65 
•60 
•50 
•40 
•65 
•45 
Diameter of Suckers : 
Largest on tentacular-arms, 
•18 
•17 
•15 
•11 
•18 
•10 
•13 
.. 
Largest on 3d pair 
•18 
•16 
•14 
•11 
•21 
•14 
•14 
_ _ 
Largest on ventral arms, 
•11 
11 
•10 
•09 
•11 
•09 
•07 
-- 
-- 
Proportions : 
Length of fin to mantle length, 1 : 
2-60 
2-50 
2-50 
2-58 
2-48 
2-58 
2-57 
2-71 
Breadth of fin to mantle length, 1 : 
2-04 
1-86 
1-82 
1-87 
1-69 
1-97 
1-84 
215 
Length* to breadth of fin, 1 : 
1-27 
1-34 
1-37 
1-37 
1-46 
1-30 
1-39 
1-26 
Length of head to mantle, 1 : 
6-14 
5-70 
6-211 
8-87 
6-70 
9-30 
7-20 
7-12 
-- 
The same specimens, included both in this and the following tables, show small 
differences in their measurements (made at different times), due partly to the different 
degrees of extension employed in measuring them, and partly to the fact that the 
alcohol had been changed, and its strength altered. 
* The length of the fin, in these tables, means the distance from the lateral inser- 
tions to the tip of the tail, which is somewhat less than the extreme length. 
