KITTON, ON DIATOMACE^. 13 



the gonidia of the common Physcia parietina, L. ; and, as in 

 the case of Kiitzing's results, though I have had no oppor- 

 tunity of confirming the observation, I have no reason to dis- 

 beheve its correctness. On the contrary, we are on the eve, 

 I beUeve, of important discoveries, calculated to increase 

 materially the number of links in thai chain, which connects 

 the Lichens with the higher and lower Cryptogamia, and 

 even with the Phaenogamia* 



Remarks on some of the New Species of Diatomace^ 

 recently published by the Rev. E. O'Meara. By 

 Frederic Kittox, Norwich. 



Having studied the Diatomaceae for many years, I am 

 convinced that a large proportion of the new genera and 

 species obtained from dredgings or deposits have no claim 

 to that distinction ; no satisfactory generic or specific 

 characters can be deduced from form procured from such 

 sources. It is also a great error to suppose that the locality 

 from whence a dredging is obtained is the habitat of the 

 forms found in it. In the majority of instances the valves 

 only are found, perhaps only one, perhaps only a fragment. 

 The fact that only one valve or frustule is found, is of itself 

 sufiicient evidence that we do not know its habitat (it may 

 be a few yards off or a thousand miles away). The li\ang 

 diatom multiplies with great rapidity ; if we found its true 

 habitat, it would occur in myriads and not as a rare or unique 

 specimen. 



The forms found in dredgings, &c., have probably been 

 deposited by the decay of animal and vegetable matter, as 

 Noctilucpe, Ascidians, moUusks, seaweed, &c., and brought 

 there by ocean currents from far distant localities ; or it may 

 even happen that they have been washed out of some 

 diatomaceous deposit by river action, and carried forward to 

 the ocean, and at last deposited amongst the debris of recent 

 species. I have been induced to make these remarks by the 

 publication of two papers (' Mic. Jour.,' Vol. VII, n. s.), by 

 the Rev. E. O'Meara, on "New Species of Diatomacege pro- 



* The character of their cellular tissue, of their chemical constitution, of 

 their contained raphidian or other crystals, of their spiral vessels (recently 

 observed in Evernia prunastri, L., byA dmiral Jones, ' Dublin Quarterly 

 Journal of Science,' Jan., 1865, p. 91) form strong points of resemblance to 

 floveering plants. 



