60 



Insects. 



ated, the cilia or setae being long, especially at the extremities, where 

 the antennae are knobbed or dentated on the upper surface. Immedi- 

 ately above the long antennae are the two short ones, each consisting 

 of only about two or three articulations, and furnished with setae : the 

 antennules, as in the genus Cyclopsina, to which this insect is nearly 

 allied, are divided into two branches, which are terminated by rather 

 long cilia. On each side of the body, attached to the sides of the in- 

 sect, we see four feathery bodies, which spread out straight from the 

 body, the use of which I do not know ; they did not appear attached 

 to the legs, nor did their movements seem apparently connected with 

 them. Being regular in number and situation, they would appear to 

 belong to the insect and not to be parasitical. The legs are each fur- 

 nished with numerous setae or branchial filaments, as in all the other 

 insects of this order. The last articulation of the tail is bifurcated, 

 each of the divisions sending off two long filaments and a short one. 



o. Oitbona splendens. b. Oithona plumifera. The line shows the natural size of both. 



Inhabits the Atlantic Ocean. " May 27, 1832, in lat. 3" 24' N. long. 

 22** 07' W.; during the middle watch, the sea was observed to be ex- 

 tremely luminous. In the morning drew up some water from along- 

 side, and upon examining it found several small animals in it, one of 

 which is the one here described." — Private Journal. 



