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PACIFIC SCIENCE, Vol. XIX, October 1965 
undulations or opening and closing of the arms 
might be quite significant. Robson (1929:22, 
28) also stated that the web is probably used 
in locomotion. He commented that the web 
becomes deep independently in the Cirromorpha 
and the abyssal Octopodidae and that this con- 
vergent resemblance is suggestive of some iden- 
tity of adaptation. 
Verrill (1896:74-75), by deducing function 
from structure, put forth several possibilities as 
to means of movement for members of this 
group that conflict with the above opinions. He 
felt that Opisthoteuthis was a crawling or creep- 
ing form, having concluded that the union of 
the eight arms with the web formed a disc-like 
ventral foot, and therefore, was analogous to 
that of a chiton or limpet. The small lateral fins 
indicated to him that Opisthoteuthis could 
swim, more or less, and that undulatory move- 
ments of the lateral edge of the pedal disc 
might be possible. But he felt that a pulsating 
swimming motion by the umbrella, similar to 
that of Cirroteuthis, would not be possible be- 
cause adhesion of the arms and web to the body 
would prevent their free use. It can be seen that, 
by approaching function in this manner, his 
deductive reasoning was, for the most part, 
erroneous. 
Certain Octopodidae have also been ob- 
served to swim by opening and closing the web. 
Verrill (1882:373) states that Bathypolypus 
arcticus swims in this manner, as does Eledone 
moschata, according to Orbigny and Ferussac 
(1840). Wells (1962:3) comments that Cirro- 
thauma employs a jellyfish-like locomotion. An- 
other species of Eledone, E. cirrosa, uses its web 
only when sinking downwards (Isgrove, 1909: 
472-473). 
The main function of the swimming pattern 
could be to facilitate travel from one area to 
the next. This is indicated by the fact that one 
specimen was apparently captured three fath- 
oms above the bottom in an off-bottom trawl. 
If bottom currents were strong enough, the ani- 
mal could travel considerable distances by 
swimming off the bottom and allowing the cur- 
rents to carry it passively. Shorter movements 
could be made by orientation forward together 
with umbrella pulsations. A combination of 
these two methods would allow the greatest for- 
ward progress. 
Another possible function might be food con- 
centration. At times the animals were observed 
just off the bottom of the aquarium making in- 
complete swimming motions. Could this pos- 
sibly represent a method whereby food is con- 
centrated by means of the produced currents? 
Once the food was concentrated, the animal 
could settle to the bottom with the umbrella 
open. This might trap the food organisms 
under the umbrella and permit feeding. 
An escape function is indicated from the 
reactions of provoked individuals in an aqua- 
rium: they moved rapidly upwards when 
prodded. 
Habitat 
It is generally felt that members of this 
group (with the exception of 0 . medusoides) 
are bottom dwellers. This conclusion has been 
deduced by several authors through arguments 
from structure to habitat (Berry, 1952:184; 
Dollo, 1912; and Meyer, 1906). The pigmenta- 
tion, depressed form, dorsal eyes, and general 
body shape all are indicative of a benthic exist- 
ence. Observations and data from this paper 
are further supporting evidence for a benthic 
existence. 
Even though numerous drags along the Co- 
lumbia River trackline have been made shal- 
lower and deeper than the known bathymetric 
range of this species, the captures of flapjack 
devilfish are restricted to the interval from 250 
to 450 fathoms (457-823 m) . This indicates 
that the species is benthic; for if it were pelagic, 
and if the trawl captured these animals while 
being set or hauled, we would expect to have 
captures over a wider depth range. The one off- 
bottom capture, which might be argued as 
being pelagic, should still be classed as a bot- 
tom capture, because of its proximity to the 
bottom. 
Extensive midwater trawling off central and 
northern Oregon by Oregon State University 
personnel has not produced a single flapjack 
devilfish (Dr. William Pearcy, written commu- 
nication). This is further supporting evidence 
of a non-pelagic existence. 
Observational data further support a benthic 
existence. The negative buoyancy, together with 
the manner in which the animal swims off the 
