1082 



CRUSTACEA. 



Abdomen three-jointed, first joint oblong. The long seta of the cau- 

 dal stylets is two-thirds as long as the body, and is naked or not 

 plumose. The furcate process of the beak is long and slender. 



The multiarticulate character of the smaller branch of the posterior 

 antennae may authorize the institution of a new genus, or subgenus, 

 for this and allied species, for which we propose the name Eucalanus. 

 The above species will be E. attenuates. 



Genus RHINCALANUS, Dana. 



Calano ferrnd affinis. From valde angusteque productus, rosfro breviter 

 crassdque infra furcato. 



Near Calanus. Front long produced and narrow, beak below short 

 and stout furcate. 



The species of this genus have the legs and antennae of Calanus, 

 with a narrow elongate, rostriform head, as in the preceding species, 

 but with a stout furcate beak, directed downward from its extremity. 

 The beak approaches that of some Pontellae. The body is unusually 

 long and slender. Among the caudal setae, the second is probably very 

 long : our specimens were mutilated in this part. The species below 

 are referred to the genus Calanus in the Proceedings ofiheAmer. Acad. 

 Sci., ii. 19, as G. rostrifrons and G. cornutus. 



Rhincalanus rostrifrons. 



Qracillimus. Frons valde elongatus, subacutus. Gephalothorax antxcl 

 paulo angustior, posticd rotundatus, b-articulatus, articulo postico 

 brevi, articulis penidtimo antepenultimoque posticl acutis. Antenna 

 anticce corpore valde longiores, leviter arcuato3, late divarkatm, apicv- 

 bus f route anterioribus, seta articuli secundi lo?igiuscidd, setis apicalibus 

 articulo vix longioribus, duabus subapicalibus posticis long is. Abd(h 

 men curium. Styli caudales fere duplo longiores quam lati, setu 

 latissimd diffusis. 



Very slender. Front much elongate, subacute. Cephalothorax five 

 jointed, penult and antepenult segments acute either side, the last 



