XI 



PHYLUM MOLLUSCA 



307 



nectives, form a ring round the gullet. There are a pair of 

 large eyes situated on the head. In the cuttle-fishes and 

 other Dibranchiata these have a highly complicated structure, 



FIG. 192. Sepia officinalis, jaws. A, in 

 situ; B, removed and slightly enlarged. 

 ( From the Cambridge Natural History,) 



FIG 193. - Sepia officinalis, enteric 

 canal, a, anus; b. d, one of the 

 bile ducts; b. m, buccal mass; c, 

 caecum; z', ink-sac; i. d, ink-duct; 

 j, jaws; /, /, liver lobes; ce, oesoph- 

 agus; p, pancreatic appendages 1 ; 

 r, rectum; s. g, salivary glands; 

 st, stomach (From the Cambridge 

 Natural History.) 



and contain representatives of all the principal parts of the 

 eye of a fish or other vertebrate. In Nautilus the eye is of 



1 This organ is by Sedgwick regarded as renal in its nature, being the 

 unpaired portion of the kidneys. (See Sedgwick's Text-book of Zoology, 

 i, pp. 433,437.) 



