in ihc Eye of the Sepia Loligo. 197 



the anterior iris shaped body just described, to be composed 

 chiefly of fibres, and to terminate in a semi-cartilaginous plate 

 of no great breadth ; but I have not yet been able to deter- 

 mine the nature of these fibres. Lastly, It is invested by a 

 reduplication of the conjunctiva, which is reflected upon it 

 from the inner surface of the sclerotic, and from it over the 

 anterior surface of the crystalline humour. 



Finally, it is to be carefully noted, that the two sets of fibres 

 which fix the lens in its position, and pass in a short way be- 

 twixt its hemispheres, do not pervade its whole thickness, but 

 suddenly terminate, uniting themselves intimately to the ex- 

 ternal layers of the crystalline humour, and leaving its central 

 portion clear for the passage of the rays of light. But there 

 is a peculiarity in the structure of this part of the crystalline 

 humour which does not seem to have been remarked. The 

 two distinct sets of fibres which I have described as fixing; the 

 lens in its situation, are chiefly connected each with the more 

 external layers of its corresponding hemisphere ; there is con- 

 sequently left between them a small space filled with a dark- 

 ish pigment, which space communicates with a wedge-like ca- 

 vity, extending all round from the outer to the central portion 

 or nucleus of the lens. Even here we distinctly perceive a 

 darkish line passing over the nucleus of the lens ; but I could 

 not positively make out whether this wedge-like cavity was 

 filled simply with a fluid, or whether, as is most probable, a 

 very delicate membrane also traversed the whole thickness of 

 the lens. External to the membranes described, is the sclero- 

 tic, seemingly of a cartilaginous nature, having a circular 

 opening anteriorly, into which the lens projects, there existing 

 neither cornea nor aqueous humour. It is perforated posteri- 

 orly by numerous foramina for the transmission of the nerves 

 proceeding to form the retina. 



The external aspect of the sclerotic is invested by a mem- 

 brane, which I consider as analogous to the conjunctiva, ex- 

 cepting that, in the cuttle-fish, its internal layers are evidently 

 muscular. It projects considerably beyond the anterior ter- 

 mination of the sclerotic, to form a true and highly moveable 

 iris; a thin layer is reflected upon the inner surface of 

 the anterior portion of the sclerotic, and is thence transmitted 



