

^Q74 CRUSTACEA. 



timd dimidio breviore, apicalibus brevibus. Abdomen 2-articulatum 

 (an adultum ?) . Styli caudales paulum oblongi. 



Front obtuse. Cephalothorax five-jointed, the last segment of the 

 thorax but little broader at extremity than the abdomen, and 

 behind very short acute. Anterior antennae a little longer than 

 the body, arcuate at base, and then straight and slightly inclined 

 backward, the tips a little behind line of beak; setae mostly short, 

 the two posterior subapical long, the longer equalling last four 

 joints, anterior penult half shorter, the apical short, spreading, one 

 anterior subremote from apex. Abdomen two-jointed (possibly not 

 adult), second segment oblong. Caudal stylets twice their breadth 

 in length. 



Plate 74, fig. 4 a, animal, enlarged ; 4 b, extremity of antenna. 



Collected in the Pacific, July 7, 1841, latitude 45° north, longitude 

 153° west. 



This species resembles the flavip&s in the abdomen, and in the last 

 thoracic joint being but little broader than the abdomen ; also, in the 

 stylets and antennae. But the form of the cephalothorax is elliptical, 

 the posterior angles are minute points, the front is rounded instead of 

 triangulate. On these grounds the species are considered distinct. 

 The anterior antennae have the setae of the fourth joint of the anterior 

 from the extremity very short before and behind ; on the next pre- 

 ceding, there is an anterior seta nearly as long as the joint. The basal 

 joint is oblong, and a shorter anterior to the oblong joint was not ob- 

 served. 



Calanus appressus. 



From obtusus. Cephalothorax postice" angustior, angulis posticis elongate 

 acuiis abdominem appressis, §-articulatus, articulis posticis longitudine 

 subcequis. Antenna anticce corporepaulo longiores, duplo leviter curvatas, 

 articulo ultimo valde graciliorequam penultimus; setis brevibus, duabus^ 

 posticis subapicalibus prcelongis, mbaequis, strenuis, anticd penultiina 

 dimidio breviore, apicalibus articulo non Imigioribus. Styli caudales 

 breves, setis diffusis, mediocribus, secundis longioribus. 



