184 Mr. J. D. Dana on some genera of Cyclopacea. 



outward. Posterior thoracic legs in male very long, and the 

 right one subcheliform. Beak pointed, in lateral view emargi- 

 nate. 



c. Posterior thoracic legs in the male large, the two unequal, and 

 the right subcheliform ; the right one of the anterior antennae in the 

 same sex having a geniculating joint about one-third its length from 

 the apex. 



Genus 5. Pontella*. Anterior antennae multiarticulate, the 

 setae as in Calanus. Maxillipeds much larger than the first pair 

 of legs, not flexed, and having the terminal joints short and seti- 

 gerous, the setae extending forward to the mouth and setulose, as 

 in Acartia ; the first pair of legs small and short, not prehensile. 

 The right posterior thoracic leg in the male large cheliform, the 

 left smaller and often simple. Beak furcate. Caudal setae more 

 or less spread. [There is a large glassy appendage under the head, 

 with a rounded or reniform summit.] 



Genus 6. Candacia, Dana. Anterior antennae and posterior 

 thoracic legs nearly as in Pontella ; the first pair of legs much 

 larger than the maxillipeds, elongate and flexed forward, with the 

 extremity inflexed and bearing a pencil of long naked setae, mo- 

 tion in the line of the body. Front truncate ; caudal setae usually 

 not spread. Colour often in part black or nearly so. 



3. Palpi of the mandibles and maxilla obsolete ; two simple eyes ? ; 

 also two oblate lenses in the front, and two prolate lenses pos- 

 terior to these within, which may constitute another pair of eyes. 



Family 4. Coryceid^e. Tentacles short, few-jointed ; external 

 ovaries two. 



Genus 1. CoRYCiEUsf, Dana. Body not depressed. Abdomen 

 abruptly narrower than the body, 2- or 3-jointed ; second pair of 

 antennae subcheliform, larger than the first pair of legs (nearly 

 as in the genus Ergasilus). 



Genus 2. Antaria, Dana. Similar to Corycceus, but having 

 the second pair of antennae terminating in a few moveable setae, 



* The name Pontia, applied to this group by Milne Edwards, was pre- 

 viously applied to a genus of insects, and has therefore been changed as 

 above. The genus Cetochilus of Roussel de Vauzeme does not differ essen- 

 tially from Pontella. 



f See Proceed, of Acad. Nat. Sci. of Philad. for October 1845, p. 285. 

 The two lenses in these animals are separated by an unobstructed space, and 

 appear beyond doubt to serve for the transmission of light. In contact with 

 the posterior lens behind is an oblong spot of dark pigment. The only other 

 supposition with regard to their nature which I can suggest, is their pos- 

 sible connection with phosphorescence. But such an arrangement for this 

 end is not probable; and moreover I was never satisfied that the species were 

 phosphorescent. 



