1914.] NATURAL SCIENCES OF PHILADELPHIA. 219 



A NEW DIATOM. 

 BY CHARLES S. BOYER, A.M. 



Chaetoceros elmorei n. sp. Plate X. 



Prof. C. J. Elmore, of Grand Island College, Nebraska, sent me 

 recently a slide containing a form of Chcetoceros. On first examina- 

 tion, the species appeared to resemble C. wighamii Br. On receipt, 

 however, of material which was subjected to a closer examination, 

 I have concluded that the species is new. The material had been 

 dried upon blotting paper and it was necessary to soak it for a long 

 while to secure filaments of the proper size, it being impossible, of 

 course, to resort to the proper methods of cleaning. The character 

 of the chromatophores is not known. I have, however, succeeded in 

 mounting a number of slides which show quite clearly the structure 

 of the valves and spores. 



All species of the genus Chcetoceros have heretofore been considered 

 as marine, and have not been found inland except in the Caspian 

 Sea. The species about to be described is found in Devils Lake, 

 North Dakota. 



It may be of interest to give a- brief description of the locality 

 from the Second and the Sixth Biennial Reports of the State Geological 

 Surveij of North Dakota, of the years 1903 and 1912, respectively. 

 In the Report for 1903, from an article by Mr. E. J. Babcock, Water 

 Resources of the Devils Lake Region (p. 208), and also from an article 

 by Mr. Howard E. Simpson, The Physiography of the Devils-Stump 

 Lake Region, in the Report for 1912 (p. 105), the following information 

 is obtained'.. 



Devils Lake is in Lat. 48° N., Long. 99° W. It is a glacial lake and 

 "occupies a basin formed largely by morainic ridges." Its length 

 is "about twenty-four miles, and the width averages, perhaps, 

 between four and seven miles." It lies at an elevation of about 

 fourteen hundred feet, and its greatest depth is not more than 

 twenty-nine feet. No streams of any size enter the lake, its chief 

 source of supply being the annual rainfall from the surrounding 

 ridges, and it has no outlet. Although originally a large fresh- 

 water lake, it is now much reduced in size, and its waters "may be 

 termed alkaline and brackish, since they show a salinity of about 



