38 PROCEEDINGS OF THE ACADEMY OF [Jail., 



its maximum width considerably in front of the posterior border, 

 and the anterior border line is somewhat straighter than usual, 

 resembling C. prasinus in this respect. This segment is to the 

 entire thorax as 5 : 8. The fourth segment is regularly, semicircu- 

 larly excavate on its posterior margin. Forbes finds the posterior 

 edges of the first three segments irregularly notched, but the fourth 

 smooth. I am unable to verify this observation; all the thoracic 

 .segments of specimens examined by me had smooth posterior edges. 

 The thorax is about twice as long as wide and one-third as long again 

 as the abdomen. 



In the male the cephalothorax (PI. II, fig. 7) tapers only a very 

 little. The first segment is distinctly concave on its anterior border. 

 It expands abruptly in its anterior third, but its middle does not 

 attain the width of the preceding thoracic segment. The first three 

 segments have smooth or faintly uneven posterior margins. The 

 last segment Forbes notes to be "peculiar in lacking the usual fringe 

 of spines on the posterior edge." I have noted on either side of the 

 anal opening peculiar, out-curving, hook-like projections of the 

 chitin (PI. II, fig. 8) on the posterior border of the fourth abdominal 

 segment. Otherwise its edge is smooth. It is interesting to note 

 that half-way between the anterior border of the anal opening and 

 the posterior margin of the third abdominal segment there are 

 present in this, as in all the Cyclopidce, two peculiar button-like 

 projections whose function vasiy be sensory (PI. II, fig. 8). 



The stylets (PI. II, fig. 8) are rather slim and about twice as long 

 as the fourth alidominal segment. Their length is four times their 

 width. The lateral spine is inserted slightly beyond the middle of 

 each ramus and from this point half-way to the posterior margin 

 of the stylets, they are in the female peculiarly excavate. Along 

 the curving line that marks this character there is a very minute 

 row of spinules. The outer apical seta is rather short and finely 

 plumose. The other three apical setse are all well developed. The 

 outer is to the inner as 4 : 3. The middle is the longest and is to the 

 next in length as 3 : 2. Though Forbes has shown the inner borders 

 of the stylets to be densely and coarsely plumose in his fig. 4 of 

 PL XV, he fails to mention this character in his description. I have 

 never seen a specimen of C. modestus with the stylets as densely 

 ])lumose as he shows them to be. All of the specimens examined 

 from this locality showed very fine and often unevenly distributed 

 hairs on the inner surfaces of the stylets (PI. II, fig. 8). They are 

 only visible under a high power. 



