BUB.NE : ANATOMY OF SEPIA OFFICINAXIS. 



55 



The position and general appearance of this funnel (present only 

 in the male) seem clearly to indicate that it is the remains of a former 

 channel of communication between the peritoneal sac surrounding 

 the genital duct and the body-cavity, thus supplying an additional 

 argument in favour of the cselomic origin of the sac. 



II, On the Presence of a Series of Cartilages in the 

 Eranchi^, 



The gill of a cuttlefish ' is an elongated structure, tapering 

 towards its apex and triangular in cross-section; it is attached to 

 the inner surface of the mantle along the greater part of one of its 

 sides, and covered on the other two by the closely-set branchial 

 lamellae arranged parallel to one another at right angles to its 

 long axis. 



In transverse section (Fig. II) it will be seen that as the lamellae of 

 opposite sides approach the base of attachment of the gill, they become 



Fig. II. — Portion of the gill of Sepia ojici/ialis, L., seen in transverse section. X Ih 

 The branchial lamellae and their supporting membranes have been removed on 

 the right side. 



at. membrane for attachment of gill to mantle, h-.ffl. branchial gland, br.l. branchial 

 lamellae, ct. cartilages, m. muscle, s.m. supporting membrane of the branchial 

 lamellae. 



pointed and widely separated from each other ; the space between 

 them is mainly occupied by a large glandular mass (the branchial 

 gland) running from end to end of the gill. The inner margins of 

 the lamellae are not, however, attached directly to this ; but indirectly, 

 by means of an intervening membrane (the supporting membrane). 



^ The gill of the Cephalopoda has been very fully described by Joubin, Arch. 

 Zool. Exper., tom. iii (1885), p. 75. 



