864 The Crustacean Nebalia and its Fossil Allies, [November, 



neither closely homologous with those of the Decapoda (Mysis 

 or Cuma) or the Copepoda. 



The 2d antennae of the male is said by Claus to be very long, 

 and to resemble those of male Cumaceae, but upon a comparison 

 of the stem of the antennae, it is in Cuma quite different in the rel- 

 ative length of the three joints. So also, while, as Claus observes, 

 they are like the antennae of the Amphipoda, this resemblance is 

 quite general ; on the whole, however, the antennae of both pair 

 bear a general resemblance to the Malacostracous type ; also, on 

 the other hand, they may also be compared with the more primi- 

 tive Copepodous type. 



The mandibles (PL xm, Fig. 4 ; Fig. 2, wd).— These are remark- 

 able from the small size and weak development of the biting edge 

 or mandible itself compared with the palpus. The oval or biting 

 end of the protopodite is small, and armed with comparatively 

 few and weak setae, which shows that the living Phyllocarida prob- 

 ably feed on decaying animal and vegetable food, which is easily 

 brushed into the mouth by their slight stiff bristles. The palpus, 

 however, is enormously developed, extending out quite to, if not 

 a little beyond, the edge of the carapace (Fig. 1). It is three- 

 jointed ; the 2d a little longer than the basal, and swollen at the 

 base, while the 3d is somewhat longer but slenderer, and edged 

 with a fringe of close-set, rather stiff setae. Though so im- 

 mensely developed as to the palpus, and entirely unlike the man- 

 dible of the Phyllopoda, in which only the protopodite is devel- , 

 oped, it may be compared with the mandibles of the Decapoda, 

 especially of Mysis and other Schizopods, 1 in which a very long 

 three-jointed palpus is developed. But the very long and large 

 mandibular palpus and very weak protopodite may be set down 

 as a diagnostic feature of the living Phyllocarida, though the 

 mandibles of the fossil species appear to have been much larger. 



The 1st Maxilla (PI. xm, Fig. 2 m*\ Fig. 5 mx\ 5 a).— These 

 are likewise singular and diagnostic features of this order, as rep- 

 resented by their structure in the Nebaliadae. They consist of a 

 small lobe (Fig. 5 a, cx x ) with about eight stout setae, and a larger 

 lobe (ex 2 ) with the outer edge fringed with long coarse setae, one 

 of which is a large ciliated seta ; from this arises, after bending 

 on itself at its base, an extremely long and slender multiarticular^ 



Compare G. O. Sars' Monographic over Mysider, 1870, PI. I, Fig. 8. Claus 

 states that the large palpus is very similar to that of many Amphipoda, but appar- 

 ently overlooks the still closer resemblance to that of Mysis. 



