358 HANDBOOK OF INVERTEBRATE ZOOLOGY. 



posterior chamber (k), separated from each other by the 

 lens (l). 



(i.) The anterior chamber opens in Loligo to the exte- 

 rior by a small orifice (Fig. 176, c), situated at the ante- 

 rior angle of the eye. 



Fig. 1«8. 



Fig. 188. — Section through the head and eyes of a young specimen 

 of Loligo Pealii ; magnified about twenty diameters. ( Drawn from na- 

 ture by W. K. Brooks. ) 



a. Dorsal muscles of head. b. Ventral muscles of head. c. (Esopha- 

 gus and salivary ducts, d. Pedal ganglion, e. Nerve commissures to 

 brachial ganglia. /. Nerves to muscles of head. g. Optic ganglion. 

 h. Ganglionic layer of retina, i. Layer of rods of retina, k. Posterior 

 chamber. I. Lens. m. Pupil, n. Ciliary ganglion, o. Cornea, p. Iris. 

 r. Cartilaginous capsule of eye. 



(ii.) The outer wall of the anterior chamber, in Loligo, 

 is formed by a transparent cornea (Fig. 188, o), which is 

 part of the general integument of the body. In Omma- 

 strephes the cornea is represented by two movable lids, 

 and the anterior chaml)er opens directly into the water. 



(iii.) Inside the cornea a circular fold (p) runs forwards 

 over the ball of the eye, to form the iris, which surrounds 



