Z PEOCEEDIXGS OF THE NATIONAL MUSEUM vol 70 



In both papers the characteristics of the European viridis are stated 

 as being the concave anterior margin of the receptaculum seminis, the 

 ciliated furca, the lack of joint in the spine of the terminal segment 

 of the fifth foot, and the spinal formula for the terminal segment 

 of the swimming feet, 2, 3, 3, 3. Apparently authentic collections 

 of this form in America are very few. As mentioned by Marsh in 

 the paper of the Canadian Arctic Expedition, the only certain iden- 

 tifications are of a collection from Edgewater, X. J., by Chambers, 

 one from Green Bay, Wis., by Marsh, and this collection made by 

 Myers in Florida. Presumably the species is found at least in the 

 intervening regions, but it appears to be somewhat rare. 



DIAPTOMUS FLORIDANUS, new species 



A small form. The last cephalothoracic segment is somewhat 

 expanded laterally and each side bears two pronounced spines (fig. 1). 

 The fifth segment of the female bears a blunt spine, projecting back- 

 ward, on the dorsal side (fig. 2). 



The first segment of the female abdomen (fig. 3) much exceeds 

 in length the rest of the abdomen. It is much dilated in front and 

 moderately so laterally. It bears on each side, well forward, a rather 

 large acute spine. The second segment is very short and is nearly 

 or quite covered by the overlapping posterior margin of the first 

 segment. The third segment and the furca are nearly equal in length. 

 The branches of the furca are ciliated on both interior and exterior 

 margins. 



The antennae reach beyond the furca. The right antemia of the 

 male is much swollen anterior to the geniculating joint; the ante- 

 penultimate segment bears a stout recurved hook which is about one- 

 half the length of the penultimate segment (fig. 4). 



In the fifth feet of the female (fig. 5) the spines of the first basal 

 segments are prominent and acute. The lateral hairs of the second 

 basal segments are slender. The length of the first segment of the 

 exopodite is more than twice its width. The second segment of the 

 exopodite is a rather stout hook, of slight curvature, and is dentic- 

 ulate on both margins. The third segment is distinct and armed 

 with two spines, the inner being long and slender. The endopodite 

 is one segmented, shorter than the first segment of the exopodite, 

 and with the tip armed with two slender spines. The tip is setose. 



The basal segments of the male fifth feet (fig. 6) are armed with 

 the customary spines which are rather prominent and acute. The 

 second basal segment of the right foot is slightly longer than wide 

 and has the lateral hair near the distal end of the segment. The 

 first segment of the exopodite is short, its length being about two- 

 thirds of its width. The second segment is nearly quadrangular in 



