154 PKOP. OWEN ON NEW AND EAEE CEPHALOPODA. 



the production of the hook prevents the application of the soft unlincd free margin of 

 the cup ; the free surface continued into the cavity is subplicate. 



Figure 4 (PI. 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, a) are shown : — a, the pedicle ; J, the acetabulum ; c, 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 tlie 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 EnoploteutMs 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 infei'red to have been part of that captured during the 

 great navigator's " First Voyage," I submit three drawings of the natural size (reduced 

 in PI. 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 tcgumentary and muscular mass has undergone in the 

 process of desiccation, the total length of this portion is 1 foot 5j inches ; the extreme 

 breadth between the fins is 6f 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 cooJcii 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 (PI. 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 Enojiloteutkis which presents this form of the 

 terminal fins. The nearest approach to it is made by the Enoiiloteiithis 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 EnopJotcuthis leptura. Leach ^, each fin has a 

 right-angled triangular figure, and they do not extend to the end of the body. In Enop- 

 loteutMs lesueurii, d'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. 340, Onychoteuthis, pi. ix. figs. 2 & 3. 



' Op. cit. p. 337, Onychoteuthis, pi. ii. fig 4, pi. xi. figs. 6-14. 



^ Op. cit. p. 339, Onychoteuthis, pi. xi. figs. 1-5. 



