1062 



CRUSTACEA. 



reddish-yellow colour, and one is full half as long as the body of the 

 animal. The animal swims by saltations, with great agility. The 

 position of the antennae in the figure may not be exactly correct, as 

 the drawing was made before the importance of this character was 

 appreciated. 



CALANUS LEVIS. 



Frons obtusus. Cephalothorax rnediocris, postich subacutus. Antenna 

 anticce corpore vix longiores, duplo leviter curvatce, apicibus J route non 

 anterioribus ; setis brevibus, 4-5 remotis longioribus, apicalibus et anticd 

 penultimd fere articuli longitudine, posticis penultimd antepenultimd- 



. quepaulo longioribus, subcequis, anticd antepenultimd obsoletd. Styli 

 caudales parce oblongi, setis rectis, appressis, abdominis longitudine. 



Front obtuse. Cephalothorax moderately stout, obtuse or subacute 

 behind. Anterior antennae fully as long as body, slightly doubly 

 curved, tips not in front of line of beak ; setae short, four or five at 

 intervals somewhat longer, apical and anterior penult nearly as 

 long as respective joints, posterior penult and antepenult a little 

 longer, subequal, anterior antepenult obsolete. Abdomen three- 

 jointed. Caudal stylets sparingly oblong. Setae parallel, about as 

 long as abdomen. 



Plate 73, fig. 1 a, animal, enlarged ; 5, extremity of anterior an- 

 tenna. 



Obtained off Eio Janeiro, January 7, 1839. 



Length, one-twentieth of an inch. The cephalothorax is rather 

 broader posteriorly. The three posterior segments are about one- 

 third whole length ; and the articulations between them are without 

 a sulcus, so that the body in an upper view has apparently an unin- 

 terrupted surface. The last three joints of the anterior antennae are 

 longer than the preceding. The longer setae of the anterior margin 

 proceed from the second, sixth, eleventh, and fifteenth joints; of the 

 apical setae two are directed backward a little obliquely, and two for- 

 ward, more obliquely. 



Fig. 2 a, Plate 73, represents another individual, obtained a few 



