REPORT ON THE PHYLLOCARIDA. 7 



differ from each other, as also from the typical genus, by the different development of the 

 phyllopodous or branchial legs. While in the one form, Paranebalia, both the endopodal 

 and exopodal parts of these limbs are very elongate, so as somewhat to approach the 

 form of the legs met with in the Euphausiidse, these parts are in the other form 

 Ndhaliopsis, so very much reduced as to cause these limbs to appear as merely simple,, 

 slightly lobular plates. We have thus, as regards these limbs in the recent Phyllocarida, 

 a series of modifications tending in the one case to render them apparently more adapted 

 for the prehension of food, in the other case to restrict their function to solely respiratory 

 purposes ; the genus Nehalia occupying in this respect an intermediate position. 



According to this difference in the structure of the branchial legs, the three recent- 

 genera of Phyllocarida may be characterised as follows : — 



Branchial 

 legs 



well 

 developed. 



scarcely projecting beyond the edges of the carapace, endo- 

 podite narrow, indistinctly jointed, exopodite forming a 

 broad rounded plate, epipodite very large, expanded at 

 both extremities, ....... 



projecting far beyond the edges of the carapace, endopodite 

 very elongate and slender, almost pediform, exopodite 

 also rather produced and ending in a narrow point, 

 epipodite exceedingly small, nearly obsolete, 



Nebalia, Leach.. 



Paranebalia, Claus_ 



imperfectly de^'eloped, lamelliform, endopodal and exopodal parts only 



slightly indicated as small triangular lobes, epipodite well defined, . Nebalio^Jsis, n. gen.. 



