146 Transactions.— Zoology. 
` Fins.—The fins are large and thick. They are attached to the sides of 
the body near its anterior aspect, and start from the mantle-border or close 
to it. They at once begin to expand, and their outline forms a curve 
widest at about its middle. They extend somewhat beyond the extremity 
of the body and coalesce. Their margin becomes thin, and often allows the 
coloured dorsal integument to shine through its substance like a purple 
band. Below the dermal layer is a thick muscular coat, whose fine but 
well-marked fibres extend from the inner to the outer margin of the fin. 
At the widest part of the fin they are parallel, but on either side they begin 
to radiate towards the outer margin, this radiation being most marked on 
the upper side. As the extremity of the body is approached they become 
less noticeable, and immediately opposite the extremity are not generally 
observable. On both aspects of the fin they are usually visible through the 
epidermis, and where they are most marked can be distinctly felt with the 
finger. " 
On the anterior aspect of the body the line of union of the fins is dis- 
tinctly visible, although the fins are so apparently a continuation of the 
mantle that there is no marked depression. 
Head.—The head is broader than long, its greatest width being at the 
projecting eyeballs. Behind these it contracts to a kind of “ neck,” similar 
to that noted by Professor Owen when speaking of Sepia palmata (Trans. 
Zool. Soc. of Lond., vol. xi., part 5). Below the eyes there is also a well- 
marked contraction at the base of the arms, though this contraction is not 
so striking as the upper one. The anterior surface of the head is flattened, 
and between the eyes is a depression which lodges the anterior production 
of the mantle-border when the neck is contracted. The posterior surface of 
the head is also flattened and has a marked depression which lodges the 
funnel. The eyes are on the sides of the head and are directed straight 
outwards. They present the character of the family in being covered with 
skin. When the tentacles are extended the sacs for their partial reception 
are easily discovered by pressure. 
The ridge of integument (pl. iii. b) running behind the eye and parallel 
with its curve, and which Professor Owen in his description of S. brevis 
(Trans. Zool. Soc. of Lond., vol xi., part 5) regards as an external ear, is 
very well marked, amounting indeed to a groove covered by a fold of integu- 
ment. This organ is, so far as I can discover, the same that is regarded by 
Professor Huxley Anatomy of Invertebrated Animals, 1877), and by Pro- 
fessor Macalister (Introduction to Animal Morphology, 1876), as olfactory 
in function. It is neither so large nor so striking as in Loligo vulgaris, 
figured in Professer Nicholson’s Manual of Zoology, p. 428 of sixth 
edition, 
