680 MB. J. GBAHAM KEKR OX THE [June 18, 



projects parallel to the axis of the buccal mass — quite free and 

 separated by a deep groove from the hood and tentacle-mass. 

 Tongue-liJie in form, its margins are inrolled about a longitudinal 

 axis, so that one comes to overlap the other. AVhich does so 

 appears to be quite inconstant in different individuals, and in any 

 one individual the right and left margins present exactly the same 

 appearance ; there being nothing to point to one in particular 

 being kept habitually folded over the other. From this, and from 

 the general nuiscular character of the funnel, I have little doubt 

 that the living animal possesses the power of unrolling and 

 flattening it out, possibly even of using its broad lower face to 

 creep on or adhere to rocks. In spirit-specimens one can readily 

 so unroll the funnel, and when this is done the appearance of the 

 animal is very striking, as is shown in PI. XXXVIII. fig. 1, where, by 

 the way, the mantle-flap has been partially removed so as to afford 

 a better view of the creature. One is here impressed, first of all, 

 by the sharp way in which the funnel is marked off from the hood- 

 tentacle-head mass. Everywhere a deep groove separates them \ 

 There is nothing here to suggest or even support the view that 

 part of the foot has grown up round and become fused with the 

 head. Again, the great size of the organ is very impressive — more 

 especially its width from side to side, — and its entire condition 

 is such as at once, to my mind irresistibly, to suggest that in this 

 organ one has the representative of the whole of the foot of the 

 ordinary Gasteropod. 



The general relations of the parts in Nautilus impress upon one 

 that :— 



(1) The hood-tentacle complex is preponderatingly anterior 

 (dorsal) to the buccal mass, its posterior (ventral) parts 

 being relatively insignificant. 



(2) The hood-tentacle complex is most sharply marked off 

 from the funnel by a deep groove. 



(3) The funnel is enough, in itself, to represent the whole of 

 the Gasteropod foot. 



Considering merely them alone, there is no suggestion of doubt 

 that the hood-tentacle complex is cephalic ; that the funnel is the 

 (lasteropod foot. 



It is because, at the present time, after many j'ears of contro- 

 versy, the contrary view, which for shortness may be referred to 

 as the ' pedal ' view, has gained the ascendency and has come to be 

 the one enunciated by the most authoritative text-books ^ that the 

 present discussion seems necessarj\ 



When Lankester published his 'Encyclopaedia Britannica' 

 article on MoUusca, he pointed out that the view taught bv 

 Leuckart, Loven, Huxley, and himself, that the Cephalopod arms 



^ In this connection the figure given by Lankester (Zoological Articles, fig. 91), 

 though very corroborative of the view there advocated, seems scarcely in accord 

 with the actual conditions. 



^ Lang's Lelirbueh, pp. 587, and Korschelt and TTeider, p, 1176, 



