146 Transactions. — Zoology. 



Fim. — 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 (pi. hi. 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. 



