1092 



CRUSTACEA. 



specimen figured, in another it was shorter, and more resembled this 

 part in the pubescens. The posterior thoracic legs represented on the 

 Plate, were figured from this specimen. 



Genus UNDINA, Dana. 



Frons infra tenuiter furcatus. Antenna anticce longce, angulo ante 

 medium leviter flexce sed articulo geniculante non instructs. Maris 

 pes posticus dexter grandis et prehensilis, ac in Pontella. Pedes antici 

 subelongati, fere ac in Calano et non geniculati. Maxillipedes pedibus 

 anticis vix minores. Oculi inferiores nulli, superiores coaliti. 



Front below slender furcate. Anterior antennae long, slightly bent at 

 an angle, but not having a geniculating articulation. Eight poste- 

 rior feet of male large and prehensile, as in Fontella. Anterior feet 

 subelongate, of same form as in Calanus. Maxillipeds nearly as 

 large as the anterior feet. No inferior eyes, the superior coalesced. 



The Undinae have the general habit of the Calani. The anterior 

 antennas in the males have no geniculating joint, but in both males 

 and females they are slightly bent, about one-third of their length 

 from the base. Like the Pontellaa, they have the posterior thoracic 

 legs large and prehensile, while unlike them, the anterior feet have 

 lateral motion, and are not smaller than the maxillipeds. The an- 

 tennas have the usual position in the Calani, the tips not being ante- 

 rior to the line of beak or but slightly so. They are also near the 

 Euchaatse, from which they differ in the maxillipeds not being thrown 

 forward nor geniculate. The cephalothorax consists of four or five 

 segments. The beak is similar to the same in Calanus. 



Uhdina, Dana, Proc. Amer. Acad. Sci., ii. 22, where the following new species are 

 briefly described. 



Undina VULGARIS. 



Frons obtusus. GepJialoiJiorax k-articulatus, posticd rotundatus. An- 

 tenna? anticce corporis longitudine, ad artictdum octavum leviter 

 reflexce; setis brevibus, setd articuli tertii longd,flexd, setis apicalibus 



