76 KANSAS ACADEMY OF SCIENCE. 



a basal segment, which has a short plain bristle, and of a terminal seg- 

 ment which has three plain bristles, of which the middle one is some- 

 what longer than the lateral ones. The cemental gland is exactly the 

 same as that of C. Clausii, and is contained in the massive first segment of 

 the abdomen. The fourth abdominal segment has a row of slender spines on 

 its posterior edge. The branches of the fork are thick, and are provided, in 

 addition to the six usual bristles, with one more small spine, which is situated 

 on the exterior side of the branches. The bristles on the corners of the 

 branches are very short, and are slightly furnished with sparse hairs; the 

 other bristles are quite long; on the two main bristles the plumosity begins 

 at quite a distance from its base. Both of the middle bristles are longer than 

 the whole trunk; one is .93. mm. and the other is .87 mm. long. The eye is 

 situated at the base of the long rostrum. The front and the lateral edges of 

 the pigmental spot are convex, and the other is concave. 



Cyclops ornatus. Length of the female, 2.4 mm.; male, 1.8 mm. The 

 front, broadened part of the body is twice as long as the abdomen. The 

 posterior edges of all the segments, except the first and fifth of the thorax, 

 are furnished with blunt teeth. The anterior antennre are very short, and 

 do not reach to the posterior edge of the anterior thoracic segment. The first 

 segment is the longest. The third, seventh and eighth are almost of the same 

 length as the basal segment. The three terminal segments are short. The 

 terminal segment has five or six large and one small bristle; the eighth, 

 ninth and tenth have each two bristles. The posterior antennse are very 

 short, and consist of four short segments. The rudimentary foot consists of 

 one segment, which has three very short bristles. The first abdominal seg- 

 ment is concave, short, and has at the sides two quite long plumose bristles. 

 The other abdominal segments are very short, so that the whole abdomen, 

 without the furca, is somewhat longer than the three posterior thoracic seg- 

 ments. The fourth abdominal segment has on its posterior edge two kinds 

 of spines : firstly, long slender ones, situated along the whole lower edge of the 

 segment; secondly, two groups of thick spines of three each. The furca is twice 

 as long as the last abdominal segment; its branches are thickly covered with 

 long hair on its interior edges. The caudal setie are plumose, equal in length 

 almost to the entire abdomen. (The length of the abdomen is .67 ram., and 

 the length of the middle bristle is .62 mm.) The plumosity of the large 

 caudal setse begins at quite a distance from their base. The color is yellow- 

 ish green. 



Cyclops longicaudatus. Length of the whole body, L39 mm., of which .6^ 

 is taken up by the abdomen and the furca. The trunk seems still longer, 

 because all the thoracic segments, beginning with the third, get suddenly 

 narrow and become almost of the same width as the abdominal segments. 

 In consequence of this form of the segments, it seems as if the body proper 

 consisted in all of two segments, (to wit, of the first thoracic and the head 

 segments, which had been fused, and of the second free thoracic segment,) and 



