116 MR. OWEN’S DESCRIPTIONS OF 
from its oviducts, and attached to the shell. When first captured, the ova were pressed 
down into the back part of the shell; but upon the removal of the superincumbent 
weight of the animal, it would appear that their own elasticity, combined perhaps with 
the absorption of fluid, and the coagulation of the albumen by the alcohol, had tended 
to occasion their protrusion forwards. 
The longest diameter of the shell is nine lines ; the transverse diameter six lines : the 
length of the animal, from the fundus of the sac to the end of the longest arm (the se- 
cond), one inch four lines ; the length of the sac, from its fundus to the free margin at the 
base of the funnel, five lines. The funnel extends beyond the base or uniting membrane 
of the ventral pair of arms; it is, as in the other genera of Octocera, unprovided with 
an internal valve; but is articulated at its base by two lateral joints to the mantle. 
The account of this structure in the Philosophical Transactions does not convey an 
adequate or correct idea of what the present specimen of Ocythoé Cranchii presents ; 
there appears indeed to be a typographical error in Dr. Leach’s description. I find on 
each side of the base of the funnel, immediately above the insertion of the lateral mus- 
cular pillars, a small firm fleshy tubercle, above which there is a small depression ; on the 
inside of the mantle immediately opposite, there is a corresponding tubercle and cavity, 
but their positions are reversed, the tubercle being above the cavity; thus the promi- 
nences in the funnel and mantle are reciprocally received into the opposite depres- 
sions, and the funnel and mantle are locked together by a double ball and socket joint, 
in the degree of apposition necessary for the complete fulfilment of the vigorous alter- 
nating muscular actions on which the respiratory function depends (a, b, fig. 14. Pl. XXT.) 
The arms in Mr. Bennett’s Argonauta hians were not rigidly contracted, as happens 
generally with those specimens which are immersed alive in spirits ; but were flaccid and 
flexible, and well adapted for determining their exact proportions and form. The length 
of the first pair was nine lines ; the number of suckers on each of these was thirty-six ; 
they extend, as in Argonauta Argo, along the circumference of the terminal membrane, 
but not to the same distance. I could not trace them with the microscope further than 
about one third of the way down from the anterior margin of the membrane; while in 
Arg. tuberculata they may be traced along more than half the circumference of the velum ; 
pule, e. g., instances of soft-bodied invertebrates secreting as true a shell as the calcareous Argonaut, yet having 
as little of a muscular attachment or uniform position to the shell, and as much freedom of quitting their shell 
and returning to it, as the Argonaut. 
With respect to another argument*, in favour of the parasitism of the Cephalopod of the Argonaut, which, 
from an imperfect knowledge of the circumstances attending the development of the ova of the Mollusca, was 
supposed to be afforded by a difference in the size of the ova of the Ocythoé, and of that which Mr. Gray regards 
as the nucleus of the Argonaut shell; I refer to it only because it has been adopted by M. De Blainville in 
his résumé of the Argonaut question as valid in favour of the parasitism of the Ocythot: it has, however, since 
been abandoned by its promulgator, being founded on erroneous premises. (See the Magazine of Natural 
History, 1837, New Series, p. 247.) 
* See Proceedings of the Zoological Society for September, 1534. 
