154 PROF. OWEN ON NEW AND RARE CEPHALOPODA. 
the production of the hook prevents the application of the soft unlined free margin of 
the cup; the free surface continued into the cavity is subplicate. 
Figure 4 (Pl. XXXII.) shows a vertical section, in the line of curvature, of the hook 
and its supporting cup, with a subjacent part of the arm. In the enlarged outline of 
part of this section (ib. fig. 4,@) are shown:—a, the pedicle; 0, the acetabulum; ¢, its 
cavity lined by the circular base of the hook, d; e, the fleshy cushion which rises into 
the hook’s basal cavity ; f, the longitudinal fibres which retract the cushion and hook ; 
and, g, the circular fibres which protrude the cushion and hook. 
Figure 5 is of a vertical section of the posterior or convex part of the hook and ace- 
tabulum, showing the depth to which the hoop or base of the hook extends into the 
fleshy mass of the acetabulum. In Hnoploteuthis the walls of the cup are the thickest, 
and the cavity is the smallest, in the Cephalopodous class. 
Of the dried end of the body of Cook’s large Cephalopod in the Hunterian Museum 
(now no. E. 1066), which in 1830 I inferred to have been part of that captured during the 
great navigator’s “ First Voyage,” I submit three drawings of the natural size (reduced 
in Pl. XXXI.), one of which, fig. 4, is rather a diagram of the end amputated, which is 
at the fore part of the origin of the pair of terminal rhomboidal fins. Notwithstanding 
the degree of shrinking which this tegumentary and muscular mass has undergone in the 
process of desiccation, the total length of this portion is 1 foot 5% inches; the extreme 
breadth between the finsis 63 inches. The fins, of thinner substance than the mantle, 
have undergone more loss of shape from drying; but, though shrivelled and crumpled, 
they manifest the rhomboidal form common to the rest of the genus. 
In Enoploteuthis cookii the fins attain their greatest breadth about one fifth of their 
length from the fore end of their base, gradually narrowing from the angle so formed to 
the end, or very near to the end, of the obtusely pointed termination of the body. Their 
line of attachment extends along the dorsal side of the body (Pl. XXXI. fig. 3)—at first 
within an inch or two from the lateral contour, but gradually nearing the sides as they 
descend and contract to their terminal subsidence. Fig. 2 (ib.) shows the ventral surface 
of the dried specimen; figure 4, the amputated end. 
I find no described or figured species of Enoploteuthis which presents this form of the 
terminal fins. The nearest approach to it is made by the Enoploteuthis armata, Quoy'; 
but the angles at the outer margins of the fins project, as in Onychoteuthis raptor, halfway 
toward the pointed end of the pair. In Enoploteuthis leptwra, Leach®, each fin has a 
right-angled triangular figure, and they do not extend to the end of the body. In Enop- 
loteuthis lesueurii, V Orb.*, the base of each rectangular fin commences, as in Sepioteuthis, 
at the fore end of the body, but terminates some way anterior to the pointed hind end. 
 D’Orb, op. cit. p. 8340, Onychoteuthis, pl. ix. figs. 2 & 3. 
* Op. cit. p. 337, Onychoteuthis, pl. ii. fig 4, pl. xi. figs. 6-14. 
* Op. cit. p. 339, Onychoteuthis, pl. xi. figs. 1-5. 
