THE CEPHALOPODA 287 
SS 
female, but only sixty in the male. These tentacles have laminated 
but not ciliated surfaces; they are adhesive and prehensile, and 
are retractile within special tentacular sheaths. When the animal 
is extended they radiate outwards from the mouth. In the female 
there are three tentaculiferous lobes in immediate contact with the 
buccal aperture (Fig. 255, c, @): these are the right and left and the 
ventral interior lobes. The last named (which is absent in the 
male) bears a laminated organ, supposed to be olfactory in function 
and known as Owen’s organ, in the middle of its free border (Fig. 
255, n), and fourteen tentacles on each moiety of the lobe. The 
{/ 
Fic. 254, 
Tremoctopus velifer, Verany, viewed from the dorsal side, showing the four dorsal arms joined 
together by a membrane. (After Verany.) 
right and left interior lobes bear twelve tentacles apiece. The 
muscular mass of the foot forms a broad ring round the three interior 
lobes, and is particularly thick and strong in the dorsal region (Fig. 
255, g), where it is modified to form a hood which protects the whole 
animal when it is retracted within its shell. On the external face 
of the hood is a concavity in which the spire of the shell is lodged. 
The tentacles borne on this ring are called “digital,” and are 
larger than the “labial” tentacles borne on the three interior lobes. 
The digital tentacles are nineteen in number on each side in the 
female, and are disposed more or less regularly in three unequal 
rows. It is only the dorsal pair of tentacles that belongs to that 
part of the muscular ring which forms the hood, the last-named 
