126 Journal of the Mitchell Society [ February 



species on a plate, the Barber pipette could be used to isolate a single 

 specimen as the progenitor. 



While we do not beheve that this method will be available for all 

 species of Diatoms, yet we feel sure that if it is applied to the forms 

 which will grow upon agar, a number of interesting results will follow. 

 Durham, N. C. 



Explanation of Plate 9. 



Fig. 1. Photograph of an agar plate of Niizschia amphioxys. Reduced one-half. 



Fig. 2. Photograph of a portion of an agar plate of Navicula atomus. X20. 



Fig. 3. Photograph of a portion of a colony on an agar plate of Navicula minus- 



cula. X50. 

 Fig. 4. Photograph of a portion of an agar plate of Nitzschia palea X20. 



LITERATURE CITED 



Beyerinck. 1890. Kultureversuche mit Zoochlorellen, uns. Bot. Zeit., Vol. 48, 



pp. 725-785. 

 MiQUEL. 1892, 1893, 1898. Recherches experimentales sur la physiologic, la 



morphologie, et la pathologic des Diatomees. Annales de Micrographie. Dates 



as above. 

 Miquel 1903, 1904. Le Microg. Preparateur. 

 Allen and Nelson. 1900. On the artificial culture of marine plankton. Journal 



Marine Biol., Vol. 8, No. 5. 

 KiJSTER. 1907. Kulture der Microorganism. 

 RiCHTER. 1909. Physiologic der Diatomccn. II Mittcilung. 

 Pringsheim. 1912. Kultureversuche mit Chlorophyllfiihrendcn Mikro-organ- 

 ismen. Zeit. z. Biol, der Pflanzen. Vol. XI, 305-332. 

 1913. Pt. II of above. Vol. XII, 1-108. 

 West. 1916. Algae, Vol. I. 



