A NEW FRESH-WATER AMPIHPOl) FROM VIRGINIA, WITH 

 SOME NOTES ON ITS BIOLOGY. 



By George C. Embody, 



Of Cornell University, Ithaca, New York. 



During the spring of 1908 a number of amphipods were collected 

 by the writer in a spring-fed pond near the town of Ashland, Virginia. 

 Conspicuous among them, for their large size and relatively great 

 abundance, were forms which were then supposed upon hasty exami- 

 nation to be Eucrangonyx gracilis (Smith). More careful study a 

 year later, however, brought to light characters distinctly different 

 from those mentioned in any description of the latter amphipod 

 available to me." It is believed that these characters are sufficiently 

 constant to warrant a description of this form as a new species. 



I am indebted to Dr. I. F. Lewis, of Randolph Macon College, for 

 collecting some forty additional specimens from the same pond where 

 discovered in 1908. From these it has been possible to determine 

 with some degree of accuracy the constancy of the characters noted. 

 To Prof. James G. Needham, under whose direction this study has 

 been made, I am especially grateful for constant advice. T desire, 

 also, to express my sincere thanks to Prof. S. J. Holmes for his kind- 

 ness in reading the manuscript and for valuable criticisms which he 

 has offered. 



EUCRANGONYX SERRATUS, new species. 



Description. — Eyes small, with few facets (about twenty-five); in 

 diameter averaging seven-tenths the greatest breadth of the basal 

 segment of the first antenna; circular or slight iy elongated and 

 densely pigmented with black. 



First antenna approximating one-half the length of body: peduncle 

 about one-third total length (fig. 1). with numerous seta 1 projecting 

 from different points along the lateral margin of each segment: first 

 segment equal to or slightly longer t han second, t bird one-half to two- 

 thirds of the first; primary flagellum consisting of from twenty to 

 twenty-seven segments, each of which gives oil' from its distal margin 

 two to five seta'; secondary flagellum composed of two segments, the 



"Smith, Am. Journ. Sci., ser. :'.. vol. 2, 1*71. |>. 453. Forbes, Hull. Illinois State 

 Lab., No. 1,1876, p. 6. Stebbing, DasTierreieh. Amphipoda. I. Gammaridea, 1906, 

 p. 388. Weckel, Proc. U. S. Nat. Mus., vol. 32, 1907, p. 32. 



Proceedings U. S. National Museum, Vol. 38— No. 1 746. 



299 



