470 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiii. 



When the legs are in place, this fold fits into the groove between the 

 abdomen and genital segment, and doubtless assists materially in 

 holding the egg masses in place. 



The arrangement of the spines and setae is as follows: First exo- 

 pod, 1,0; 4, II: endopod, 0, 0; 0, III: second exopod, 1,0; 4, V: 

 endopod, 0, 0; 0, VII: third exopod, 1, 0; 0, V: endopod, 0,0; 0, V: 

 fourth exopod, 5, 0: endopod, 4, 0. All the seta3 are extremely rudi- 

 mentary, and their plumes are easily overlooked. 



Of the reproductive organs the oviducts are coiled in the anterior 

 part of the genital segment. They do not extend back of the vulva, 

 which is situated in the groove between the abdomen and genital 

 segment. The external coils are intricate and very irregular, and it 

 is absolutely impossible to straighten them out, so we can only esti- 

 mate their total length, which must be at least twenty-five times 

 the length of the body. The strings are very narrow for so large a 

 copepod, and the eggs themselves are thin, so that there are several 

 thousands in each string. 



They are held securely \r\. place between the dorsal plates of the 

 genital segment and the lateral lobes of the abdomen until they 

 hatch, the nauplii escaping at the posterior end of the egg bag. The 

 cement glands are narrow and sickle-shaped, arching out on either 

 side parallel with the lateral margin of the segment. Tlie tip of 

 each gland is evenly rounded, and there are no signs of cells or other 

 divisions. 



The semen receptacle is situated just in front of the base of the 

 abdomen, but its exact shape could not be determined in any of the 

 available specimens. The spermatophores are fastened to the ven- 

 tral surface of the genital segment just in front of the abdomen and 

 lie close together on either side of the mid-line, and the duct leading 

 from each can be traced to the vagina on the opposite side, where it 

 opens close to the base of the abdomen. 



All the internal organs of the genital segment are thus confined to 

 the short space in front of the abdomen, and this is practically the 

 limit of the segment itself. But the cavity of the segment extends 

 much farther back, as can be readily proved by injecting water into 

 its anterior portion. 



In this genus, therefore, as in the others belonging to the subfam- 

 ily, the abdomen is really fastened to the ventral surface of the geni- 

 tal segment. 



Total length, 25 to 30 mm.; length of carapace on mid-line, S to 

 10 mm.; width of same, 12.25 mm.; length of genital segment plates, 

 17.75 mm.; width of same, 15.5 mm. 



Color, a uniform yellowish white, deepening in alcohol to an 

 orange brown in the center of the different carapace areas and the 



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