432 
PACIFIC SCIENCE, Vol. XIX, October 1965 
FIG. 2. Number of Opisthoteuthis Californian a 
caught per one-hour of trawling by 2 5 -fathom depth 
intervals from the Columbia River trackline. 
(Dr. Dean McManus, unpublished data). Ad- 
ditionally, at 275 fathoms (503 m), where no 
specimens were captured, outcroppings were 
encountered. The above findings are presented 
as possible explanations, not conclusions. 
Morphology 
The external appearance of animals of this 
genus is quite peculiar. General descriptions in 
the past have invariably been made on pre- 
served specimens or on specimens which were 
not alive in water; consequently the common 
name, flapjack devilfish, has arisen in the liter- 
ature. Berry (1952:183) goes so far as to state 
that in the preserved state these animals re- 
semble in about equal degree a soggy pancake 
or a very dirty floor mop. The lack of support- 
ing structures, webbing between the arms, and 
the extent of gelatinous tissue makes this de- 
scription true. But when the animal is observed 
alive in water, a different picture is presented 
(Fig. 3). 
With the mantle cavity and gelatinous tis- 
sues supported by water the shape, as viewed 
anteriorly, appears more like a wide bell than 
the plano-convex disc used to describe pre- 
served material. Viewed from the side the 
anterior portion of the head and body proper 
slope gradually dorsad, with the dorsal surface 
being rather flattened. The posterior margin 
slopes very abruptly, almost perpendicularly, 
away from the dorsal surface. Thus, the cephalic 
mass is considerably expanded and raised, being 
displaced posteriorly. 
The eye openings are not large and the 
rounded eye prominences, which are noticeable 
on the upper surface of preserved material, 
disappear when the animal assumes a normal 
shape. Conversely, the ear-like fins become 
more noticeable on live specimens. 
When the animal is at rest (Fig. 3 a), there 
is a horizontal curvature of the distal portion 
of the arms anteriorly, a condition similar to 
that described for preserved specimens (Ijima 
and Ikeda, 1895:329). The lateral curving of 
the right and left arms anteriorly results in the 
dorsal or anterior arms facing each other with 
their concavity while the ventral or posterior 
arms face with their convexity. The ends of 
the latter pair of arms are, therefore, turned 
laterally away from each other. 
When at rest in an aquarium, the oral sur- 
face did not lie flat to the bottom, as might be 
expected. Instead, the distal half of the animal 
was held off the bottom (an inch or so in 
larger specimens) with only the basal portions 
of the arms in contact with the bottom (Fig. 
3 h) . Interestingly, this area of contact on the 
arms is the portion possessing the largest suck- 
ers (excepting the 6-7 enlarged suckers dis- 
tally on the dorsal pair of arms on the males, 
which have a specialized function [Berry, 1955: 
221}). Yet, at no time were the animals ob- 
served to hold with these or other suckers. As 
TABLE 2 
Number OF Opisthoteuthis calif orniana CAUGHT PER 
One-Hour Drag with a 400-Mesh Commercial 
Otter Trawl by 25 Fathom Depth Intervals 
on a Trackline Off the Mouth of the 
Columbia River.* 
DEPTH 
(fathoms) 
NO. 
SPECIMENS (C) 
NO. 
DRAGS (f) 
C/f 
250 
1 
11 
0.09 
275 
0 
8 
0 
300 
2 
12 
0.17 
325 
2 
10 
0.20 
350 
5 
9 
0.56 
375 
9 
9 
1.00 
400 
1 2 
9 
0.22 
425 
3 
5 
0.60 
450 
1 7 
7 
1.00 
2 
1 « 
80 
* Only drags at depths where captures have been made in 
this area are included. 
C7f = 31/80 = 0.388. 
