THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL. 



Vol. XII. JUNE, 1891. No. 6. 



All cominunications for this Journal, whether relating to business or to editorial 

 matters, and all books, pa^nphlets, exchanges, etc., should be addressed to Ameri- 

 can Monthly Microscopical Journal, Washington, D. C. 



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 Trubner &= Co., S7 Ludgate Hill, Londott, or to Air. W. P. Collins, 757 Great 

 Portland street, London, accompanied by the yearly price of five shillings. 



Diatoms: Their Life History and their Classiflcation. 



By Rev. FRED'K B. CARTER, 



MONTCLAIR, N. J. 



[With Frontispiece.] 

 {Cojitt?iued from page loi.') 



It is not claimed that the points mentioned will always be sufficient, 

 but they will in many cases, especially when studied with the help of 

 the figures of the fresh-water and fossil forms, and the beginner will be 

 able to make enough progress to spur him on to identify, by closer study 

 and the use of more elaborate keys, such forms as puzzle him ; whereas, 

 at first, such a key, especially if it included all the genera, fresh-water, 

 fossil, and marine, might frighten him, and possibly make him 

 think it too much trouble to attempt the classification at all. For the 

 drawings, I am indebted to the kindness of Mr, Robert W. Smiley, who 

 performed a like service for me in connection with my paper on the 

 Desmids, and I wish to express my thanks to him here. After the 

 student has made himself familiar w^ith the fresh-water and fossil forms, 

 if not before, he will surely want to own a copy of Wolle's fine work 

 on the Diatomaceae of North America (if he can possibly do so I would 

 advise his obtaining it at once, as the number of copies is limited), and 

 I add here a list of references to his illustrations of the marine forms 

 just mentioned : 



List of Figures in the Frontispiece. 



Fig. 30. Synedra fulgens. Fig. 41. Coscinodiscus argus. 



31. Goiiiothecium Roger.'^ii. 42. Arachnoidiscus Ehrenbergii, var. Cali- 



32. Hercotheca mammillaris. fornica. 



33. Biblarium ellipticuni. 43. Actinoptychus (Omphalopelta) areola- 



34. BiblariunnStylobiblium) clypens. tus. 



35. Periptera tetracladia. 44. ActinoptyLhus undulatus. 



36. Dicladia capreolus. 45- Actinocyclu.s Ehrenbergii. 



37. Hemiaulus bifrons. 46- Heliopdta nitida. 



38. Eupodiscus argus. 47- Asterolampra rotula. 



39. Auliscus Grunowii, var. Californica. 48. Asterolampra (Asteromphalos) Hiltoni- 



40. ^ystephania raeana. ana. 



Copyright, i8gi, by C. W. Smiley. 



