ANIMAL NATURE OF DIATOME.E. 449 



Schizonema Smilhii, Agardh. 



The testimony of Kiitzing, and a comparison with an 

 authentic English specimen, obligingly supplied by 

 Berkeley, convince me that the Schizonema which we 

 have most abundantly of all in the Lagunes of Venice, 

 belongs to this species. I was led away before from this 

 conclusion by the exclusive locality of Sidmouth, indi- 

 cated by Kiitzing, and the comparison of specimens with 

 which I was favoured by Harvey, of which we shall speak 

 by and by, by the difference of measurement, and the 

 evident presence of partial tubes. Kiitzing says the 

 length of the Naviculae is ^th of a line, or 0'054, and, as 

 usual, gives a figure less than half the size he mentions, 

 ( 1-1 millim. (^) = 0-026.) I find the greatest length 

 to be constantly 0'044, the breadth of the secondary 

 elliptico-elongate surfaces 0-012, and that of the primary 

 slightly elliptico-truncate 012. As to its generic posi- 

 tion, I observe that Harvey places this species in his 

 section Schizonema, corresponding to the Micromega of 

 Agardh and Kiitzing. 



Finally, though incidentally, it is right to make a 

 remark here on the practice, with even the most con- 

 scientious authors, of copying references without verifi- 

 cation. Both Harvey and Kiitzing copy from Agardh 

 the reference to Ulvafcetida of English Botany (pi. 2101), 

 whilst in that classical work there is only the Conferva 

 fcetida, and the Ulvafcetida of Vaucher is merely cited, 

 by mistake, as synonymous. 



i 



Schizonema sirospermum, Kiitz., (Micromega.) 



Though not appertaining to this series, I here advert 

 to this species, because the specimens just mentioned, 

 with which I was favoured by the celebrated Harvey 

 under the name of S. Smithii, belong to it. Kiitzing 

 informed me that he had received them, without a name, 



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