DR. COBBOLD ON THE EYE OE THE COD-EISH. 



145 



where it is accompanied by a blackish shade ; discal point black ; 

 exterior border cinereous, this hue attenuated hindward. Hind wings 

 with a cinereous fringe. Length of the body 6 lines ; of the wings 

 16 lines. 



The structure of this species does not quite agree with the typical form 

 of Xyssia. 



199. Nyssia ? bigutta.ta, n. s. Foem. Cinereo-fusca, alis anticis pal- 

 lide cervinis, gutta discali nigra, spatio exteriore obliquo fuscescente 

 intus linea nigro-fusca concisa marginato. 



Female. Cinereous brown, stout. Palpi ponect, very broad and obtuse. 

 Antennae simple. Fore wings pale fawn-colour, excepting the oblique 

 exterior part, which extends from near the tip of the costa to the mid- 

 dle of the interior border, and is blackish brown and concise along 

 its inner side ; discal dot black, rather large. Length of the body 5 

 lines ; of the wings 14 lines. 



[To be continued.] 



Histological Observations on the Eye of the Cod-fish (Morrhua 

 vulgaris), with especial reference to the Choroid Griand and the 

 Cones of the Eetina. By T. Spexceb Cobbold, M.D., F.L.S., 

 Lecturer on Botany, Zoology, and Comparative Anatomy at 

 the Middlesex Hospital College. 



[Head March 6th, 1862.] 



By introducing observations of this kind to the Linnean Society 

 I am aware that I am treading a well-beaten path ; but as there 

 are still many points connected with the minute anatomy of the 

 vertebrate eye which remain to be solved, I trust that the facts 

 and opinions which I proceed to bring under the Society's notice 

 will obtain due consideration. 



With the exception of Mr. Nunneley's researches, most of the 

 recent investigations into the minute structure of the eyeball 

 have been made after the organ in question had been steeped for 

 a longer or shorter time in chromic-acid solutions ; and from this 

 circumstance I think we have been frequently led into error as 

 regards the precise character of the ultimate elements of the organ, 

 although, in the hands of Hannover, Kolliker, and Heinrich Muller 

 more especially, the relations of the component layers of the eyeball 

 have been most satisfactorily determined. 



To take the vitreous humour, for example, it is quite clear that 

 Hannover's views (published in Muller's ' Archiv' for 1845) as to 



LI>'X. PBOC. — ZOOLOGY, YOL. YI. 10 



