DESCRIPTIONS OF THREE SPECIES OF SA]!^D FLExVS 

 (AMPHIPODS) COLLECTED AT NEWPORT, RHODE 

 ISLAND.' 



By Sylvestek D. Judd. 



While at Mr. Agassiz's Newport laboratory in the summer of 1893^ 

 I collected a large number of crustaceans. Of these, the Amphipods 

 particularly interested me. Tliey were obtained by skimming the calm 

 surface of Narragansett Bay at night with a "tow net." 



Most of the Amphipods found in the skimmings or " tow ''belonged 

 to the family Gammarida', a typical representative of which is Gam- 

 mar us ^ ovir common Sand Flea. 



CALLIOPIUS RATHKEI (Zaddach). 



Some little olive-colored Gammarids, which might at first be taken 

 for (lammarus, proved to be very interesting. Unlike Gammarus, they 

 did not rise to the surface of the water with a succession of springs, 

 but moved rapidly through the water at a uniform rate. They often 

 bumped against the side of the dish, but never stopped the incessant 

 vibration of their legs until a secure hiding place had been reached. 



Female— A large white shield on the back formed a conspicuous and 

 distinctive feature by which they were easily recognized. These Am- 

 phipods agree with the description of CaUiopius rathlei given by Sars^ 

 more closely than with the description of any other known species. 

 However, they constantly differ slightly from the European form^ of 

 that species in certain details, as for instance antennal sense organs, 

 color, etc., which are sufticiently constant to warrant their description. 



The points of dift'erencc may be considered in tlie following order: 

 Color, size, coxa', and calceoli. 



1 For the invaluable aid received iu the preparation of this paper, I have to thank 

 Dr. W. Faxon and Prof. E. L. Mark, of Harvard University. 



2 Crustacea of Norway, 1893, I, Pt. 20. 



■'For the sake of fonveniencc, I shnll allude to the animals hitherto described, as 

 tlic European forni— to those which I have studied, as the American form— of CaUi- 

 opius ntihlei. 



^-OTE.— Abl>reviations: <(»/. anterior; r7. dorsal ; (7is/. distal ; /.lateral; »i. )iio.liau; 

 j)ot. posterior; px. proximal; r. ventral. 



Proceedines of the United States National Mnseuin, VOL. XVIII— No. 1084. 



593 



Proc. N. M. 95 38- 



