THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY, 



No. 46. AUGUST 1841. 



XLIV. — On Gloionema paradoxum. By the Rev. M. J. 

 Berkeley, M.A., F.L.S. 



[With a Plate.] 



The genus Gloionema has been long considered as consisting 

 of productions of a very doubtful nature. Some of its species 

 indeed have been rejected as the ova of insects ; but notwith- 

 standing the communication of Roberge* to the Linnaean 

 Society of Paris, who is stated to have proved by repeated 

 experiments that Gloionema paradoxum is not a vegetable, the 

 species is still retained by Agardhf. Kutzing J also, who re- 

 jects the other species as ova, though he refers to Agardh's 

 treatise, and therefore must have known of Roberge's expe- 

 riments, still retains this, and has published it as an alga in 

 his ^ Decades.^ Kiitzing, indeed, informs us that he kept his 

 specimens in water for many weeks or even months without 

 obtaining any positive result ; and Prof. Nitzsch, to w hom he 

 communicated the production, was not more successful. 



No detail of M. Roberge^s experiments, as far as I am 

 aware, has as yet been published ; I have therefore no hesita- 

 tion in offering to public notice my own observations, made 

 at the end of last May, which completely confirm the report 

 of Roberge, and which must be considered as quite decisive. 



I have not indeed had an opportunity of comparing my in- 

 dividuals with authentic foreign specimens, but they agree so 

 completely with Kiitzing's description, that I have not the 

 least doubt of their identity. 



So early as 1825 I found a small patch at Cherry Hinton, 

 near Cambridge, and communicated a sketch to Dr. Greville. 

 The production was however considered of so doubtful a na- 

 ture that it was not published in my ^ Gleanings of British 

 Algae,' nor is it included in the English Flora. I did not meet 

 with it again till May 25, 1841, wdien I found a large mass 

 at King's Cliffe, forming a loosely reticulated mass of tortuous, 

 very elastic, yellow-green threads, several inches in extent, 



* Linn. Soc. Par. 1827, p. 47. 



f Conspectus Criticus Diatomacearum, p. 30. 



+ Bot. Zeit. 1833, vol. ii. p. 513. 



Arm, ^ Mag. N, Hist, Vol vii. 2 G 



