162 



Mr. L. W. Bailey presented the following paper : — 

 New species of Microscopical Organisms, chiefly from 



THE River Para. By Loring W. Bailey, Cambridge, 



Mass. 



The species of Diatomaceae here described as new, together with 

 other species contained in the accompanying list, were obtained 

 chiefly from soundings made by one of the United States Exploring 

 Expeditions, in the River Para, and the mouth of the Amazon, in 

 the year 1854. The soundings were submitted to my father, Prof. 

 J. W. BaUey, for microscopic examination, and by him most of the 

 following species were discovered, and drawn for the purpose of pub- 

 lication. As neither the drawings nor the descriptions have ever yet 

 been pubhshed, and as many of the forms are still new to microscop- 

 ists, I have endeavored, by reference to the unpublished letters and 

 memoranda of my father, and the study of the original specimens in 

 the possession of the Society, to complete the work of describing and 

 figuring the beautiful forms which this locality contains. 



As nearly six years have elapsed since these forms were first ob- 

 served, it is probable that some, at least, of the species here described 

 as new, may have been seen, and perhaps named, by other writers. I 

 have, however, carefully examined aU the books at my disposal, and 

 am convinced that most of the forms are still quite unknown. One 

 species only, the Syringidium Americanum B., has been figured by 

 other authors. A figure of this species may be found in the last 

 edition of Pritchard's Infusoria. 



The descriptions here given are derived from the study of the 

 original forms, and from similar specimens prepared from the rough 

 material of the Society. Much assistance has also been derived from 

 pencil notes accompanying the original camera sketches. 



In several well-marked species, where no name has been given by 

 its discoverer, I have ventured to propose names, chosen with refer- 

 ence to their form or locality, and have omitted from this descriptive 

 list, several forms contained in the engraved plate, which, from the 

 absence of names and details, could not be satisfactorily distinguished 

 from species now known. 



All the forms here described as new, were originally discovered by 

 my father, but in the accompanying list I have been able to add 

 several new forms to those already seen by him. 



Plates illustrating the forms here described are now in course of 

 preparation, and will be published, together with more detailed de- 

 scriptions, in the Journal of this Society. 



Amphora delphina, L. W. B., nov. sp. 

 Frustules elliptic-oblong, with broad, slightly rounded ends; valves 

 very minutely and transversely striated ; nodules very large, extend- 



