38 Mr. J. D. Siddall on the 



Out of the forty-four genera constituting the British marine 

 fauna, representatives of thirtj-two were observed and recorded 

 from these gatherings : some types were conspicuous by their 

 absence, whilst others, especially the MilioUne genera, with 

 TruncatuUnay Rotalta, Polystomella^ and Nonionina^ appeared 

 to adapt themselves to brackish water perfectly. After tracing 

 the relation of the existing brackish-water Foraminiferous fauna 

 of the " Fen area " with that of the Post-tertiary Fen-clays, 

 Mr. Brady proceeds to give a geographical account of the 

 stations from which the material had been collected, and also 

 of the various species found, concluding a valuable and com- 

 prehensive paper with a table showing the genera and species 

 found in each locality. 



More recently* Mr. David Eobertson, F.G.S., of Glasgow, 

 has worked out, with great care and patience, the Foraminifera 

 of the Firth of Clyde ; and his results yield a list of eighty- 

 five species in all. His gatherings were made at no less than 

 forty stations, and embrace depths of all degrees from four to 

 thirty fathoms. Between these extremes there must be a wide 

 range of variation in the conditions of life, depending on the 

 depth and on the relative volume of fresh and salt water ; and 

 fuller particulars on such points would have conferred addi- 

 tional interest upon Mr. Robertson's valuable paper. 



The results proposed to be offered in the following pages 

 have been attained from the examination of the Microzoa of 

 the estuary of the Dee, the observations having extended over 

 a period of about three years — great assistance having been 

 given in this by my kind friend Mrs. Shone, who has worked 

 most indefatigably, and discovered several species of great 

 interest. The list is even a longer one than Mr. Robertson's, 

 comprising no less than one hundred species and varieties, an 

 increase of fifteen per cent, in number. Of the thirty-two 

 genera included in Mr. Brady's list, three have not yet been 

 observed in the Dee, viz. GlanduUna, Vaginulina, and Gau- 

 dryina ; but three others have taken their place, and so made 

 the number equal, viz. Bigenerina^ Spirillina, and Cassidu- 

 lina ; but the specimens of each are very small and of rare 

 occurrence. 



The estuary of the Dee from Chester down to Burton Point, 

 a distance of about 9 miles, has within the past two hundred 

 years undergone very considerable changes in outline. Many 

 thousands of acres of sand which the tide formerly flowed 

 over have been reclaimed ; and this work of reclamation is still 



* " Notes on the Ostracoda and Foraminifera of the Firth of Clyde, 

 with some Remarks on the Distribution of Mollusca," by David Robert- 

 son, F.G.S., Trans. Geol. Soc. Glasgow, 1874, vol. v. part 1, p. 112. 



