2Q96 CRUSTACEA. 



Collected several individuals, October 27, 1838, in the Atlantic, 

 latitude 4° north, longitude 19° west. 



Length, one-twelfth of an inch. Colour, in part orange or reddish 

 orange. 



The antennae have the usual slight bend after the eighth or ninth 

 joint, and the following part of the antenna consists of fifteen or sixteen 

 joints. The beak is furcate below, and the furcation is directed down- 

 ward and much inward. The cephalothorax is broadest posterior to 

 centre. The first segment of the abdomen is a little the longest, and the 

 last the shortest. The posterior antennae have the first joint of the 

 longer branch about twice the remaining portion in length; the 

 setae at apex are a little longer than the branch. 



Posterior pair of thoracic legs nearly like the preceding, dissimilar; 

 the left leg most slender, without hairs, and having very long spines at 

 the apices of the joints, which are much longer than the joint. The 

 spines at the apices of the joints of the right leg are shorter than the 

 joint, and there are a few short hairs from the inner side of longer 

 branch. The specimen described was probably a female, while those 

 of the other species appear to have been males. 



Subfamily OITHONINJE. 



The Oithoninae are related to Calanus more nearly than to Pontella. 

 As in Calanus, the eyes are the superior alone, and these occupy a 

 single minute spot. Moreover, the right antenna is not geniculating 

 in the males, and the legs of the posterior pair are rudimentary. As in 

 Acartia, the hairs of the antennae are rather long and point in various 

 directions, instead of being confined to the anterior side, like Calanus 

 and Pontella. As in Pontella, the maxillipeds are longer than the first 

 pair of legs, being much longer than in that genus, and geniculated 

 and thrown forward, instead of standing at right angles with the body. 

 The very long abdomen, the small mandibular palpus, the digitate 

 inner side of the maxillae, are characters in which the species are alto- 

 gether peculiar. Such distinctive characters belong, at least, to the 

 only genus of this family yet discovered. More particular descriptions 

 are given beyond. 



