14 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 59. 



indistinctly three-jointed, somewhat lamellar, and terminating in a 

 minute sharp point. 



First four pairs of legs biramose, each ramus three- jointed; basal 

 joint of the exopods denticulate on the outer margin; terminal joint 

 of the first endopod with one, of the second endopod with three, 

 and of the third and fourth endopods with four spines. All the 

 spines on both endpods and exopods are dagger-shaped. 



Color (preserved material) , a uniform cinnamon brown. 



Total length, 4 mm., exclusive of anal setae. Width of first 

 thorax segment, 2 mm. ; length of egg strings, 2 mm. 



/Specific characters of male. — Body smaller and narrower than in 

 the female; abdomen relatively longer and wider and four- jointed, 

 the penultimate joint the shortest. Anal laminae each terminated 

 by three unequal setae, the inner one the longest and the outer one 

 the shortest, the relative lengths being, respectively, 14, 9, 3. The 

 genital segment is considerably enlarged, and shows on the ventral 

 surface at the posterior corners the rudiments of a sixth pair of legs. 



The fifth legs are much wider than in the female, and each car- 

 ries a large seta near the distal end of the outer margin, in addition 

 to the three terminal ones, all four about the same length. 



The first antennae are narrower than those -of the female and 

 more abundantly supplied with setae. The maxillipeds are very 

 strong; the second joint is coarsely toothed along the distal half 

 of the inner margin; the terminal claw is longer than the second 

 joint and strongly curved. 



Color (preserved material), a uniform cinnamon brown. 



Total length, 2.85 mm., exclusive of anal setae. Greatest width, 

 1.25 mm. 



(hawaiiensis, a native of the Hawaiian Islands.) 



Remarks. — This species agrees so fully with the two described by 

 Sars 8 that it must be referred to the same genus. 



The distinguishing specific characters are the large size, the posi- 

 tion of the articulation in the terminal claws of the second antennae, 

 the heavier armature of the second maxillae, and the relatively 

 shorter and thicker anal laminae. Neither of Sars' species was posi- 

 tively parasitic, although leptostylis might well have been so. The 

 young females and adult male, which he recorded as " picked up 

 from the bottom residue of a large collecting bottle containing vari- 

 ous animals," could easily have been ectoparasites on one of those 

 animals and have been washed off into the bottle. The present species 

 is definitely known to be parasitic since all the specimens were taken 

 directly from its host. 



"Copepoda of Norway, vol. 6, Copepoda Cyclopoida. pt. 13, 1918, pp. 182 and 184. 



