MYSIDEA. 671 



it is more probable that they are ovarian. The particles of the blood 

 are distinct. 



Lucifer. THOMPSON, Zoological Researches, Cork, April, 1829, Part ii. p. 58 j ED- 

 WARDS, Crust., ii. 467. 



LUCIFER ACESTRA. 



Segmentum antennale non rostratum, carapace multo longius. OcuU 

 prcelongi, segmenti antennalis dimidio bene longiores, peduncido tenui- 

 ter cylindrico et gldbo apicali grandi instructs. Segmentum abdominis 

 sextum Stofere duplo longius, maris dentibus duobus infra armatum, 

 dente antico acuto, postico obtuso et recurvato. Segmentum caudale 

 lamina caudali internet duplo brevius, maris, infra gibbosum, gibbosuld 

 laid, non obliqud inclinatd. 



Antennary segment much longer than carapax. Eyes very long, 

 much exceeding half of antennary segment, having a slender cylin- 

 drical peduncle and a large globular summit. Sixth segment of 

 abdomen about twice as long as fifth, in males having an acute tooth 

 below near middle, and posteriorly an obtuse process which is 

 recurved. Caudal segment one-third as long as outer caudal lamina, 

 and half as long as the inner, below gibbous in males, the promi- 

 nence broad and not obliquely inclined. 



Plate 44, fig. 9 a, male, enlarged ; b, anterior half, more enlarged ; 

 c, side view of caudal extremity in a male ; c', caudal segment, upper 

 view; d, mandible; e, f, first and second maxillae; g, outer maxil- 

 lipeds; h, posterior extremity of thorax, showing glassy eardrop 

 organ at in' ; m", same organ, as it appeared after a short time de- 

 tached from the animal; i, outline of posterior part of thorax of 

 female. 



Pacific Ocean, latitude 6 30' south, longitude 177 east, near Sher- 

 son's Island. Caught twenty individuals, with twenty-four casts of a 

 hand net, at 7 A. M., March 24, 1841. 



Length, five-eighths of an inch. Colourless, excepting a little red- 



