230 On the Species of Lucifer. 



II. Neck longer than rest of cephalothorax. Sixth abdo- 

 minal segment shorter or not much longer than uropod. 

 Telson shorter than uropod. 



A. Eye not more than half length of neck. 



1. Eye-stalk stout. Hinder ventral spine of sixth 



abdominal segment of male sharp. 



a. Exopodite of uropod more than live times as long 



as wide. Hinder ventral tooth of sixth abdo- 

 minal segment of male followed by a pair of [1837. 

 spinules L. reynaudi, H. M.-Edw., 



b. Exopodite of uropod less than five times as long 



as wide. Hinder ventral tooth of sixth abdo- 

 minal segment of male not followed by a pair 

 of spinules. 

 i. Last leg does not reach end of neck. Eye less 

 than one-third length of neck. [Spine on 

 exopodite of uropod nearly or quite reaches 



end.] L. (tffinis, sp. n. 



ii. Last leg reaches or exceeds end of neck. Eye 

 rather more than one-third length of neck. 

 a. Spine on exopodite of uropod projects well 



beyond end, which is rounded. L.faxoni, sp. n. 

 /3. Spine on exopodite of uropod does not nearly 



reach end, which is pointed . . L. inermis, sp. n. 



2. Eye-stalk slender. Hinder ventral spine of sixth 



abdominal segment blunt L. bonitensis, sp. n. 



B. Eye more than half length of neck. 



1. Neck only slightly longer than rest of cephalo- 



thorax. Sixth abdominal segment longer than 

 uropod. 



a. Eye-stalk stout. Sixth abdominal segment longer [1852. 



than fourth and fifth together .... L. pacificus, Dana, 



b. Eye-stalk slender. Sixth abdominal segment only 



as long as fourth and fifth together . L. clausi, sp. n. 



2. Neck a good deal longer than rest of cephalothorax. 



Sixth abdominal segment not longer than uropod 

 [or than fourth and fifth segments together]. 



a. Rostrum present. Last leg nearly or quite 



reaches end of neck. Exopodite of uropod 

 blunt-ended, with terminal spine at end of 

 outer side L. batei, sp. n. 



b. Rostrum wanting. Last leg does not nearly 



reach end of neck. Exopodite of uropod 

 diminishes to a point [where the spine stands, 

 ? in L. typus], 

 i. Hinder ventral spine of sixth abdominal seg- 

 ment swollen at the end. Spine of exopodite 



of uropod well developed L. acestra, Dana, 1852. 



ii. Hinder ventral spine of sixth abdominal seg- 

 ment sharp-pointed. Spine of exopodite of ri837. 

 uropod obsolete ? L. ti/jms, H. M.-Edw., 



If my conclusions as to the species of Lucifer be correct, 

 it will appear that most of them have a distribution which, 

 whether it be wide or restricted, is limited, and not world- 

 wide. Two species alone seem at present to break this rule. 



