202 The Eye of the God-fish. 



panying plate (Fig. 1). It is probable tliat these bodies have 

 been seen by observers in this country, as their contents are 

 evidently referable to the so-called Psorospermise described by 

 J. Miiller, Creplin, Leydig, and others on the Continent. Some 

 years ago they were brought under my notice by my friend 

 Dr. Drummond, at Edinburgh, when we both endeavoured to 

 ascertain their true character. As then demonstrated, and in 

 accordance with my more recent examinations, the patches in 

 question appear to form a sort of nidus for the lodgement, pro- 

 tection, and development of the minute cells which are found 

 by myriads in their interior. These little bodies are evidently 

 parasitic in their nature, and forcibly remind one of the so-called 

 jpseudo-naviculce of Gregarina. I think that they are of a vege- 

 table nature ; this algous character being also, in my opinion, 

 applicable to the somewhat similar parasitic cells described by 

 Mr. Lubbock, F.R.S., in his valuable memoir "On the Ova and 

 Pseudova of Insects," in the Philosophical Transactions for the 

 year 1857. Be this as it may, I have further to remark, that 

 in specimens recently subjected to microscopic analysis, the 

 cellules measured about the 1 -4000th of an inch in their longest 

 diameter, and they presented an oval figure, being at the same 

 time slightly pointed at either extremity (Fig. 2). The cell -wall 

 itself is double ; but by far the most striking peculiarity con- 

 sists in the universal presence of two bright, highly refracting 

 nuclei, usually located side by side at one end of the cell cavity. 

 They also exhibit a pale yellow colour, due apparently to a clear 

 fluid surrounding the nuclei. In no instance have I observed 

 any metamorphotic appearances, neither have I seen any altered 

 condition of the cells, such as might indicate an earlier or later 

 stage of growth. On the addition of caustic potass the colour 

 of the cellules quickly disappeared, and they performed a series 

 of peculiar jerking movements, due, it would seem, to the burst- 

 ing of the outer cell-wall ; a little sarcode matter appeared to 

 make its escape, but the oval form of the cells remained un- 

 affected. 



Between the internal separable layer of the sclerotic coat 

 and the marsupium of the choroid there exists a clear albu- 

 minous fluid, which, in the perfectly fresh condition of the eye, 

 is entirely free from blood corpuscles, sarcode globules, and 

 other particles ; but this fluid is not uniformly disposed between 

 the two membranes, because at certain spots, and especially in 

 the neighbourhood of the optic nerve, the marsupium is inti- 

 mately blended with the inner sclerotic layer above mentioned. 

 The fibrous marsupium itself is in great part made up of, or 

 rather contains, numerous cylindrical rods, which offer a de- 

 cidedly inorganic crystalline aspect, but which do not consist 

 of carbonate of lime. The Neapolitan naturalist, Dellc Chiaje, 



