Decapod Crustacea of Bermuda, Part II. 53 



a third small sexual branch. Mandibles lack a palpus. Rostrum 

 small, or sometimes lacking. 



Sexes differ decidedly. The male has a conspicuous petasma 

 on the first pleopods and a special organ on the second ; two con- 

 spicuous ventral spines on the sixth abdominal segment; and a 

 prominent tubercle on the under side of the telson, all of which 

 are lacking in the female. In the latter, at least in some species, 

 the third maxillipeds are shorter than the first legs, and there are 

 apparently differences in the second maxillipeds and other organs. 

 The lateral abdominal processes are more acute in some species. 



In our species the male, at least, appears to have a pair of phos- 

 phorescent organs in the first five abdominal segments, and perhaps 

 the tubercle on the under side of the telson is also a phosphorescent 

 organ. 



Leucifer faxoni Borr. 



Lucifer typus (?) Faxon, Chesapeake Zool. Labr. Studies, Johns 

 Hopkins Univ. Biol. Labr., (iii), p. 113, pi. 7, figs. 1-3, 1879 (non 

 Thompson). (?) Bate, Voy. Challenger, Zool. Crustacea, vol. xxiv, 

 p. 464, pi. 71-83, 1888 (descrip. and metamorphoses) =L. affinis Bor- 

 rodaile. 



Lucifer, sp., W. K. Brooks, op. cit., vol. 173, pp. 57-137, pi. i-ix, 1883 

 (anat and metamorphoses). 



Lucifer faxoni Borrodaile, Ann. and Mag. Nat. Hist, Ser. 8, vol. xvi, 

 pp. 228, 230, 1915. 



(?) L. affinis Borrodaile, op. cit., pp. 228, 230, 1915 (based on Bate's 

 species). 



Leucifer faxoni Hay and Shore, op. cit., p. 381, text-figure 4, pi. xxvi, 

 fig. 10, 1918. 



PLATE XVII, FIGURES 1-7. PLATE XVIII, FIGURES 1-13. 



The specimens of Leucifer taken by my party at the surface at 

 Bermuda have been lost. The following description is based on 

 a large lot (several hundred) taken at one time in the Gulf Stream 

 at the Albatross station, No. 2711, and unusually well preserved. 



Owing to the extreme delicacy and tenuity of the species of this 

 genus various organs are liable to be lost or damaged ; others are 

 often contracted or distorted by preservatives. Therefore it is 

 advantageous to have large numbers for any careful study of their 

 structure. The sexes differ much in several respects and are 

 readily distinguishable, as stated in the generic description. 



