QUARTERLY JOURNAL 



OF 



MICROSCOPICAL SCIENCE. 



ORIGINAL COMMUNICATIONS. 



Notice of some New Species of British Fresh-Water 

 DiATOMACE^. By William Gregory, M.D., F R S.E., 

 Professor of Chemistry, 



Having examined with some minuteness the fossil Diatoms 

 in the Mull earth and in the Glenshira sand, both of which 

 deposits yielded a very large number of species, I felt desirous 

 to compare with them the species at present living in our 

 waters. Accordingly I obtained, from various friends, gather- 

 ings from a great many different localities, both in England 

 and in Scotland. Those which I have been able to study with 

 some care, up to the present time, are almost all from fresh 

 water, and, postponing to a future op])ortunity an account of 

 the marine gatherings, I propose now very briefly to notice 

 the results obtained from a number of fresh-water gatherings, 

 more especially with reference to such species as are either 

 altogether new or new to Britain. 



It is well known that in no department of Natural History 

 are the species, whether recent or fossil, so universally distri- 

 buted over the earth's surface. All the more common species 

 are found, according to Ehrenberg, in his recent great work, 

 ' Microgeologie,' not only in the Arctic and Antarctic regions, 

 but under the Equator, between the tropics, and in the tem- 

 perate zones. But few forms seem to be characteiistic of any 

 country or quarter of the globe. The remarkable ^enus Terp- 

 sincp, and a few others, have not yet occurred in Europe, but 

 are found at widely distant localities in other parts of the 

 world. A very striking example of the wide-spread distribu- 

 tion of diatoms is tliat of a beautiful little Pinnularia, which 

 I first noticed in the Mull earth, and which Mr. Smith, who 

 shortly afterwards found it recent at Grasmere, named Pinnu- 

 laria latestriata, a name which I adopted instead of P. Hebri- 

 densis. I have since met with it in at least three-fourths of 

 all the gatherings I have examined from fresh water, although 

 invariably scattered. I could find no figure of this species in 



VOL. IV. B 



