PEOr. OWEN ON NEW AND EAEE 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. J, cd, 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, e,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 (PI. 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 (PI. XXIV. fig. ^,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 the tentacles can be withdrawn is situated beneath or on the ventral side of the eye- 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 A, h 

 (PI. XXV. fig. 1). 



The aquarium enables the home-naturalist to comprehend the use of this complex 



mechanism of cephalic prehensile organs. The Cuttle makes a 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. If a fish should glide or a crab crawl within 



Fia-. 1. Yis. 2. 



sight or smell, the Cuttle is roused, opes wide its eyes, separates and stretches out its 

 arms, and manifests its emotion by change and heightening of its colour ; it then moves 

 craftily to the correct distance, takes aim, uplifts the dorsal pair of arms (i), 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) \ 



^ 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 have been witnessed at the Brighton Aquarium. 



