Description of New Species of Diatoms. 15 



January, 1875, on occasion of the visit of the American party 

 to observe the transit of Venus. Only two dredgings were 

 made, and they were almost identical. Flagiogf-afnma Robert- 

 sianufH of Greville, was also abundant, and a small and doubt- 

 fully new Surirella. Besides these, there were a few larger 

 diatoms, and especially a variety of Ajiliscus coelati/s, and as 

 the dredging continued fragments of Hypnum, Bartramia, and 

 jBarbula, washed off from the land, these explain the occurrence 

 of a few fresh water forms ; no Foraminifera were found, but 

 spines of Hemiaster caudatus were abundant. It is but justice 

 to add, that Dr. Kidder, who was the Botanist of the expedition, 

 and was therefore mainly employed in collecting the land 

 plants, was prevented from making other dredgings and col- 

 lections of Diatomacece, by the sudden and unexpected recall 

 of the party, which is the more to be regretted since the only 

 dredgings that were made have proved so fruitful; and as so 

 little is known of the Diatomacecz of high southern latitudes. 



Rhizosolenia Eriensis^ n. sp. H. L. S. Hab. Buffalo, N. Y., 

 Lake Erie, D. S. Kellicot, Esq.; Cleveland, Ohio, Lake Erie, 

 H. C. Gaylord, Esq.; Lake Michigan, Chicago, S. A. Briggs, 

 Esq. Frustules of medium size, compressed and somewhat 

 flattened; six to twelve times as long as broad; annuli on the 

 dry frustules conspicuous, altenate, and with a zig-zag median 

 connection, valves finely striate, bristles nearly or quite as long 

 as the frustules, and wath the calyptra excentric, lying nearly 

 in a line with one margin of the frustule when the flat side is 

 in view. Length of frustules .003 to .006. Plate III, fig. 7. 



This remarkable diatom, the only fresh water species of 

 Rhizosolenia hitherto known, was first sent to me living by 

 Mr. H. C. Gaylord, of Cleveland, O., who obtained it in a filter- 

 ing of Lake Erie water, used for the supply of the city. The 

 bulk of the collection was Stephanodiscus Niagarae^ which is al- 

 most always obtained in such filterings; subsequently Mr. 

 Briggs, then Editor of "77;^ Lens,'' detected it in filterings from 

 Lake Michigan, and I furnished him a description which he 

 published in his list of "Diatomaceae of Lake Michigan," in 

 Volume I. of '•^The Lens,'' page 44. It was, however, a rare form, 

 until Mr. D. S. Kellicot, of Buffalo, by making filterings at 

 different seasons of the year, finally obtained it in considerable 

 abundance. Many of the fresh water forms procured in these 

 filterings are considerably modified, e. g Tabellaria fenestrata 



