South of France and the Auvergne. 3 



occupies the hollow of an ancient crater, proved fertile in a 

 variety of forms. The eddies of the Dor, the mountain torrent 

 which drains the district, and the perpendicular surface of the 

 rock over which the stream is hurried that forms the Grande 

 Cascade, were also productive. 



From the Auvergne I proceeded to Orleans, and from the 

 source of the Loirct, three miles from that city, collected excel- 

 lent specimens of two rare and interesting forms, namely Ortho- 

 sir a arenaria, W. Sm., and Gomphonema cristatum, Ralfs. 



The 4th of July closed my herborizations, and on that day I 

 plundered one of the fountains of the Champs Elysees in Paris 

 of materials, which added a few names to my roll of French 

 Diatomacese. 



The gatherings made during the above journey amounted to 

 forty-nine, and the included species may be conveniently divided 

 into five classes. 



1st. Those which were found in the Gulf of Lyons. 



2nd. Brackish- water forms in localities under the influence of 

 the Mediterranean. 



3rd. Species which were collected in springs and rivers at a 

 low elevation. 



4th. Forms which only occurred at high elevations in the vol- 

 canic districts of the Puy de Dome and Mont Dore. 



5th. Species or varieties which have not hitherto been figured 

 or described. 



In the following lists I have underlined those species which 

 have not hitherto been found in Britain, and I employ through- 

 out the nomenclature adopted in the " Synopsis,^' whether in the 

 portion already published or in that prepared for the press. 



List 1. Mediterranean forms. 



Epithemia Musculus, Kiltz. Podosphenia L5nigbyei, Kiltz. 



Cocconeis Scutellum, Ehr. elegans, W. Sm. 



diaphana, W. Sm. Rhipidophora elongata, Kiltz. 



Eupodiscus fulvus, W. Sm. Licmophora splendens, Grev. 



Tryblionella Soleseformis, W. Sm. Fragilaria striatula, hyng. 



Surirella fastuosa, Ehr. Striatella unipunctata, Ag. 



striatula, Turp. Hyalosira d-elicatula, Kiitz. 



Araphiprora alata, Kiitz. Rhabdonema arcuatum, Kiitz^ 



Navicula didyma, Kiitz. Adriaticum, Kiitz. 



Westii, W. Sm. Grammatophora marina, Kiitz. 



Pandura, Breb. serpentina, Kiitz. 



Stauroneis pulchella, W. Sm. Biddulphia pulchella. Gray, 



Pleurosigma elongatum, W. Sm. Achnanthes longipes, Aff. 



angulatum, W. Sm. subsessilis, Kiitz. 



Synedra affinis, Kiitz. Podosira hormoides, Kiitz. 



fulgens, W. Sm. Berkeleyia fragilis, Grev. 



Podosphenia Ehrenbergii, Kiitz. 



1* 



