258 REV. £. o'm£ara. 



Grammatophora marina* Kiitz. 

 ,, maxima^ Grun. 



„ serpentina* Ralfs. 



Navicula Crabro, Ehr. 

 „ elegans, W. Sm. 

 „ pusilla, W. Sm. 

 „ rhombica, Greg. 

 ,, scopulorum, Kiitz. 

 „ didyma, Ehr. 



„ var. Y, Greg. 

 Niizsehia bilobata, W. Sm. 

 „ lanceolata* W. Sm. 

 „ parvula, W. Sm. 

 „ perpusilla, Grun. 

 Pleurosigma strigosum, W. Sm. 

 Podocystis adriatica = Surirella adriatica, Kiitz. 

 Podosira hormoides* Kiitz. 

 Synedra nitzschioides, Grun. 



Concerning Podocystis adriatica, Grunow, * Die Oster- 

 reichischen Diatomaceen/ p. 467, observes that this species 

 had not come under his notice from either the North Sea or 

 the Atlantic Ocean. Many years since I found it in abundance 

 on a specimen of Grinnellia Americana, gathered from the 

 Atlantic Ocean in the vicinity of New York, and now I have 

 found it in these gatherings from Spitzbergen. 



In a note to his work ' On the Diatoms of the Arctic Sea ' 

 Professor Cleve alludes to a paj)er of mine published in the 

 ' Journal of the Royal Dublin Society,' July, 1860, contain- 

 ing a list of diatoms found by me in gatherings made in the 

 Arctic Sea by Sir Leopold McClintock, and mentions that 

 thirty-seven of the forms included in my catalogue had not 

 occurred in any of his samples from that region. It is with 

 much gratification, therefore, I have to notice that eleven of 

 these, viz. those marked with an asterisk, have occurred in 

 these gatherings of Rev. Mr. Eaton, and, for the most part, 

 in such numbers as to leave little doubt of their being 

 indigenous. 



Cocconeis binotata, C. coronata, and C. fimbriata, seem 

 almost cosmopolitan forms. I have found them in collections 

 from various parts of the Indian Ocean, not unfrequently on 

 the West Coast of Ireland, and now also in the neighbour- 

 hood of Spitzbergen. 



The specimens of Navicula didyma, var. y, Greg. (^ Journ. 

 Micr. Sc.,' vol. iv, PL v),'.fig. 16, were of very frequent oc- 

 currence. I cannot but think this form is entitled to rank as 

 ^ distinct species. The space about the median line expands 



