1016 CRUSTACEA. 



pair obliquely sublanceolate, apex truncate, next joint small and 

 nearly round. 



Plate 69, fig. 5 a, animal, enlarged, ventral view ; b, same, dorsal 

 view; c, inner (or anterior) antennse; d, outer antennas; e, leg of 

 third or fourth pairs ; /, fifth pair of legs ; g, sixth pair ; Ji, seventh 

 pair; i, extremity of abdomen; k, h', branches of first pair of stylets. 



Atlantic, latitude 4° 25' south, longitude 21° 30' west. Collected, 

 November 7, 1838, at 4 A. m. 



Length, four lines. Colour, dark brown, with some brilliant green 

 reflections or a kind of iridescence. Head covered with hexagonal 

 facets; two oblong, masses of pigments separated by a narrow line, 

 and visible both in an upper and under view. Antennary area, seen 

 in under view, small and narrow (not over one-third the width of 

 head), anteriorly quadrate; pigment seen either side of the area. 

 Thorax has seven joints, but first two very short and partly con- 

 cealed; whole thorax but little longer than head. Abdomen not 

 abruptly narrower than thorax. Last abdominal segment consists of 

 an anterior part subquadrate, and a smaller posterior, which is trian- 

 gular, and not longer than broad ; this part is separated by a suture, 

 and corresponds to normal seventh segment; there is also a suture 

 near anterior margin of this last abdominal segment, separating fifth 

 and sixth normal segments. The posterior stylets are attached to 

 the margin of the last abdominal segment, either side of the triangular 

 termination. They have a very short base, and extend more than 

 half their length beyond the extremity of the abdomen, the branches 

 are truncate at apex and equal in length. The other stylets about 

 reach to extremity of abdomen, and have lanceolate branches. The 

 branches of first pair of stylets are serrulate on the margins, excepting 

 outer margin of outer branch. The apex of coxa of fifth pair is pro- 

 minent, and the serratures of the margin extend from this apex 

 around half way to base. 



This animal swims rapidly. It remained swimming on the sur- 

 face of the water while confined in ajar. On dying it became colour- 

 less. 



