On the British species of Poly-podium. 141 



glion of the crystalline. I considered it the expansion of a 

 nerve, before closely examining its fibrous structure and con- 

 nections." 



I can only remark on this description of Mr. Wallace, that 

 in no fish which I have as yet examined, do I find any troch- 

 lea or loop, through which the pyriform body passes : its 

 figure and size seem to preclude the possibility of such an 

 arrangement. I am bound however to state, that I have had 

 no opportunity of examining the anatomy of the organ of vi- 

 sion in this particular fish. 



As every fact relating to the perfection of the organ of vi- 

 sion, must needs possess considerable interest, I hope this im- 

 perfect account of a new structure, may induce some zealous 

 comparative anatomist to give it a further examination, and 

 favor the scientific public with a communication of the results. 



8, New Broad Street, 

 Nov. 10th, 1837. 



Art. VI. A few Notes on the British species of the genus Poly po- 

 dium, of Linnceus. By Edward Newman, Esq. F.L.S. &c. 



When among the Welch mountains, I have always amused 

 myself with admiring the infinite variety of ferns that half co- 

 ver the face of the country ; but this autumn, for the first time 

 in my life, a desire came over me to learn their names. With 

 this view, I gathered hundreds of fronds, and when arrived at 

 a quiet inn in the country, I arranged them into supposed 

 species. I found that even on those bleak and barren moun- 

 tains, where fern is cut, dried, and housed, as the only litter 

 that can be obtained for horses, three distinct species flourish- 

 ed in great abundance: but where some little rill tumbled 

 over a precipitous bank, or a ledge of rock, keeping the sur- 

 face in a state of perpetual moisture, half a score species, at 

 least, might be found: and again, where the country had 

 yielded to some attempts at cultivation, a few others made 

 their appearance. 



To those who have never dabbled in natural history, every 

 fern is l a green leaf,' and nothing more ; so is every insect 'a 

 bug,' or ' black beetle.' But the naturalist, however young in 

 his vocation, desires knowledge of a somewhat more precise 

 and definite nature ; — a name seems indispensable to him. — 

 It was not long before I set to work with Smith, and Wither- 

 ing, yet, — how shall I express my disappointment ! — after a 

 most minute and really elaborate examination, I could only 



