new microscopic alg^. 325 



Ch^toceros boreale. 



Chcetoceros boreale was discovered by Mr. Atthey on the 

 Northumbrian coast, in the stomach of Modiola vulgaris. This 

 makes an interesting addition to our list of British Diatomacege, 

 its recorded habitats having hitherto been on the Western coasts 

 of America, and in the Indian Ocean, supposing C. Peruvianum to 

 be the same thing, which is not clearly proved. The direction 

 of the horns at right angles to thefrustule in many of the British 

 specimens (PL XVI., fig. \0a) is a curious circumstance. It 

 appears doubtful whether any observer has yet met with a speci- 

 men in which the horns were entire and unbroken. Dr. Bailey 

 gives them in his figure of C, boreale as scarcely tapering and 

 ending abruptly. In the present gathering were several good 

 examples of the extremity unfortunately broken off, but still 

 showing that the horns taper gently to an acute point, as might 

 have been expected (PI. XVI., fig. 10«). Along with it occurred 

 some Polycystinea3 (hard parts of Thalassicolla, &c.), Actiniscus 

 Sirms, with Doryphora amphiceros, and other commoner marine 

 Diatomacese. 



In addition to the above I found a Closteriwn. 



Closterium aciculare, n. sp. T, W. 



Frond elongated, very slender, straight except at the extremi- 

 ties, which are very slightly curved downwards, gradually taper- 

 ing from the centre to the very acute ends. Length of frond, 

 ^i^th of an inch; greatest breadth, ^qVo^^ (^^' ^^J^*? %• l^-) 



Mr. Wm. Archer, of Dublin, who has had enlarged oppor- 

 tunities of studying the species of Closteria, with the Desmide^ 

 generally, has most kindly assisted me in the investigation of 

 this species. Amongst four species nearly allied, remarkable for 

 their great slenderness {^prcelongwn, turgidum, macilentum, p>ronum\ 

 he considers it most nearly allied to the latter, but says it is far 

 longer in proportion to the width than any Closterium he has 

 ever seen, either living or figured. M. de Brebisson, on inspection 

 of it, pronounced it distinct, and a really good new species. It is 

 to be feared this must be numbered as one of the departed glories 



2 R 



