]39 



New Species of Diatomaceje. 

 By F. KiTTON, Esq. 



In the previous number of this Journal, the Rev. E. O'Meara 

 has charged me with carelessness, and thinks if I had read 

 his papers with greater attention I should have expressed 

 my doubts of the genuineness of his new species more 

 cautiously. I have, therefore, read them again, in order to 

 apologise for any misrepresentation, and correct any errors. 

 I find two or three mistakes ; viz., Cocconeis divergens 

 should have been C. clavigera, the remarks on Navicula 

 pellucida ought to have preceded the passage quoted by the 

 Rev. E. O'Meara. I have also inadvertently made him the 

 author of Rapkoneis liburnica, whereas he is only respon- 

 sible for the variety. With these exceptions, I really find 

 nothing to retract. At page 91, the Rev. E. O'Meara 

 says : " How inapplicable are some of Mr. Kitton's observa- 

 tions on dredging to the forms found by me in the dredgings 

 from Arran." I find, on referring to his first paper, he 

 says, " this material was procured from depths varying from 

 ten to thirty fathoms," &c. I do not think, therefore, I was 

 unjustified in assuming that his material was similar to others 

 procured from like depths, and which, in almost every case, 

 consist of sand, animal and vegetable debris, and valves of 

 diatoms. My copy of the ' Microscopical Journal ' in which 

 his first paper appears has no description of the figures. I 

 therefore assumed that the figures were magnified 600 

 diameters, as that was the degree of amj^lification more 

 frequently used in the second paper. I do not find the 

 number of diameters stated in the text. If the Rev. E. 

 O'Meara refers to the text of his first paper, he will find 

 Navicula pellucida is fig. ^ ; and fig. 2 in the plate is the 

 form which, I think, resembles Navicula pandura much too 

 closely to entitle it to rank as a new species.* N. denticutala 

 is fig. 3 in text. I am still unconvinced of the specific 

 distinctness of Surirella pulchra and 5. gracilis, or that 

 they differ sufficiently from S. lata to warrant their separa- 

 tion from that species. I am willing to admit that a re- 

 markable difference exists between the figures of S. pulchra 

 and S. gracilis ; viz., the crenulate margin ; alae are also 

 wanting, but as these differences are not noticed in the text, 

 I am inclined to doubt the correctness of the figures, and 



* N. denticulata of the text is frequent in the so-called " Corsicau moss," 



VOL. VITI. — NF.W SER. M 



