252 



PROCEEDINGS Of THE NATIONAL MUSEUM. 



VOL. 42. 



The first antennae are 1 T-segmented and reach about to the third 



cephalothoracic segment. The 



twelfth segment has a sensory 

 club. The last three antennal seg- 

 ments bear a hyalme lamella with 

 a somewhat UTegular row of veiy 

 minute spines. This structure is 



Fig. 6.— Cyclops strenuus. 

 second antenna. x 148. 



Figs. 7-8.— Cyclops stkenucts. 7, Terminal 

 segments of antenna of female from syria. 

 8, Terminal segments of female from Ax- 

 ton, New York. X 292. 



shown in figures 7 and 8. Figure 

 7 is from a Syrian specimen and 

 figure 8 is from a specimen col- 

 lected at Axton, New York. These 

 are drawn to the same scale and 

 show the relative sizes from the two 

 locahties. The second antenna, shown in figure 6, has no distinctive 

 characteristics. 



The spinous armature of the terminal segments of the exopodites 



of the swimming feet is represented by 

 the formula 3, 4, 3, 3. This formula 

 held true in all the specimens which 

 have passed through the author's 

 hands. Schmeil says that it may be 

 also 2, 3, 3, 3, or 3, 3, 3, 3. Figures 9 

 and 1 show the structure of the termi- 

 nal segments of the second and fourth 

 feet. 



The fifth foot is composed of two 

 segments. The basal segment is 

 commonly broader than long, but 

 is somewhat variable in its rela- 

 tive dimensions; it bears at its 

 outer distal angle a rather short plumose seta. The second segment 

 is about twice as long as broad; it bears at its distal extremity a long 

 plumose seta and about midway of its inner margin a stout serrate 

 spine; distad of the spine the segment is about half as wide as the 



Figs. 9-10.— Cyclops strenttcs. 9, Termi- 

 nal segment of exopodite of second 

 foot. 10, Terminal segment of exopo- 

 dite of fourth foot. X 148. 



