644 CRUSTACEA. 



articulated with the obliquely truncate apical margin, just under the 

 apex, which is acute. The branches of the third pair are similar to 

 one another though unequal in size. 



At the base of each of the anterior four abdominal legs, between 

 the two legs of each pair, there was a ruby-red, shining globule ; also, 

 one on each side at base of sixth and second pairs of thoracic legs ; 

 also a large red, or brownish red spot in the back, not far from the 

 eyes. Several individuals were observed to emit light, and it was 

 seen to come from the anterior part of the cephalothorax. The light 

 was intense and had a greenish tinge. 



EUPHAUSIA GRACILIS. 



Carapax brevissime' rostratus. Articulus antennarum internarum primus 

 ad apicem parce preductus et acutus. Squama basalts antennarum 

 externarum basin multo superans. Pedes tenuissimi, articulis tribw 

 ultimis subcequis simulque sUmtis precedente vix brevioribus, setis lon- 

 giusculis, palpo parvulo, quadruple breviore. Segmentum abdominis 

 posticum lamellis caudalibus non lanyius, Qtum 5to fere duplo lonyius. 

 Sranchice posticce ramosce. 



Carapax very short rostrate. First joint of inner antennas sparingly 

 produced and acute at apex. Basal scale of outer antennae longer 

 than base. Feet very slender, last three joints subequal, and to- 

 gether but little shorter than preceding joint, setae longish, palpus 

 quite small, about one-fourth as long as leg. Last abdominal seg- 

 ment not longer than caudal lamellae, sixth segment about twice as 

 long as fifth. Posterior branchiae ramose. 



Plate 42, fig. 6 a, animal, enlarged; b, extremity of abdomen (setulee 

 of apex probably lost by mutilation) ; c, posterior branchia. 



Pacific, latitude 15 23' south, longitude 148 23' west. Caught 

 one individual during a calm at 4 A. M., September 10, 1839. 



Length, half an inch. Colour, reddish along the venter and in the 

 legs. Scale of second antennae extends beyond apex of base about as 

 far as length of penult joint of base. The last abdominal segment 



