2076 CRUSTACEA. 



3. Cephalothorax postice elongate acutus, angulis posticis remotis. 

 Calanus COMMUNIS. 



Frons rotundatus. Cephalothorax posticd elongate^ acutus, 5-articulatus, 

 articulis 4 posticis subozquis. Antennas anticce corpore paulo longiores, 

 duplo leviter curvatos, apicibus fronte non anterioribus, setis apicalibus 

 brevibus, duabus posticis subapicalibus longis, subcequis, anticd penul- 

 timd quadruplo breviore, setis totis aliis brevibus. Styli caudales 

 breves, setis diffusis, secundis duplo longioribus. 



Front obtuse. Cephalothorax posteriorly long acute and points dis- 

 tant, five-jointed, four posterior segments subequal. Anterior antennae 

 a little longer than the body, very slightly doubly curved, tips 

 not anterior to line of front ; apical setae short, two posterior sub- 

 apical long, nearly equal, anterior penult one-fourth as long, all the 

 other setae short, apical minute. Caudal stylets very short, setae 

 spreading, the second twice longer than the first. 



Plate 74, fig. 7, view, enlarged. 



Collected in the Atlantic, October 18, 20, 27, 31, and November 2, 

 3, 8, and 12, 1838, latitude 8° north to 5° south, longitude 23° to 

 15° west; also May 13 and 16, 1842, latitude 4° 30' to 1° south, and 

 longitude 25° to 30° 30' west. 



Length, one-tenth of an inch. Colour, purplish or reddish, faint. 



The four posterior joints of the cephalothorax constitute more than 

 two-fifths of its whole length. Among the caudal setae the second is 

 about half longer than the others. There are five pairs of natatories, 

 of which the first pair is the shortest, and the fifth the next shortest. 

 Eyes minute. Last joint of antennae a little longer than the preceding. 

 Abdomen four-jointed, first segment a little the longest. 



Calanus am^inus. 

 C. communi quoad antennas anticas setasque caudales affinis. Cephalo- 



