PROF. OWEN ON NEW AND RARE CEPHALOPODA. 135 
contract to their terminal attachment, which is at about one third of the length of each 
arm from its free pointed end; at the terminal part a ridge is continued from the subsidence 
of the web along the outer or peripheral side of the arm (Pl. XXIV. fig. 1, a’, a’). 
The tentacles, d, d, rather exceed the length of the body when outstretched ; their 
comparatively slender subcylindrical stems slightly narrow to their abruptly expanded 
extremities, ¢, f, g. These are chiefly formed by the acetabuliferous disk, the proximal end 
or margin of which, projects freely from the supporting pedicle. The acetabula are 
somewhat irregularly disposed, and are unequal in size ; the four or five largest, greatly 
exceeding in size those of the arms, are at the middle and rather toward the proximal 
end of the terminal disk (Pl. XXV. e, e) ; they decrease in size towards its circumference to 
that of the brachial cups. The dorsal surface of the cup-bearing disk is transversely fur- 
rowed (Pl. XXIV. fig. 1, f) ; the border of the tentacle opposite that which supports the 
disk is produced into a narrow fold or “ velum” (ib. g). The large cavity or sac into which 
the tentacles can be withdrawn is situated beneath or on the ventral side of the eye- 
balls: the wrinkled disposition of its parietes in the empty state is shown at h, h 
(Pl. XXV. fig. 1). 
The aquarium enables the home-naturalist to comprehend the use of this complex 
mechanism of cephalic prehensile organs. The Cuttle makesa hollow in the submerged 
sand on which it rests; the tentacles are drawn in, out of sight, the arms are contracted 
and collected en masse, as in the cut, fig.1. Ifafish should glide or a crab crawl within 
Fig. 1. Fig. 2. 
craftily to the correct distance, takes aim, uplifts the dorsal pair of arms (1), divaricates 
the side pairs (2, 3, 4), and, darting out the tentacles, seizes and draws in the prey with a 
rapidity the eye can scarcely follow (fig. 2) *. 
1 T am indebted for this statement, and the drawings from which figs. 1 and 2 are taken, to my late esteemed 
friend Mr W. A. Lloyd, Conductor of the Aquarium at Westminster, and lately in charge of that at the 
Crystal Palace. The same phenomena haye been witnessed at the Brighton Aquarium, 
