PACKARD.] ANATOMY OF NEBALIA. 435 



pared with the mandibles of the Decapoda, especially of Mysis and other 

 Schizopods,^ in which a very long three-jointed palpus is developed. 

 But the very long and large mandibular palpus and very weak j^rotopo- 

 dite may be set clown as a diagnostic feature of the Fhyllocarida. 



The 1st maxillce (PI. XXXVI, fig. 2, mx^; fig. 5, mx^-, 5 a). — These are 

 likewise singular and diagnostic features of this order, as represented 

 by their structure in the Nebaliadce. They consist of a small lobe (Fig. 

 5 a, cx'^) with about 8 stout setae, and a larger lobe {cx^) with the outer 

 edge fringed with long coarse setse, one of which is a large ciliated seta; 

 from this arises, after bending on itself at its base an extremely long and 

 slender muliiarticulate process (or endopodite?) which, in the female, 

 is directed upward and backward (Fig. 5 a, en), reaching to the tergum 

 of the basal abdominal segment, and ending in two very long slender 

 setae, while a few other similar setae arise, one from each joint.^ In the 

 male of N. geoffroyiy according to Claus, the long setose process is 

 directed forwards and downwards. 



The 2d maxillce (PL XXXVI, figs. 2, 5, mx"^).— These are entirely unlike 

 those of the first pair, and unlike the Decapodous or Phyllopod type. 

 They consist of a basal portion composed of four thin, delicate, unequal 

 lobes (Fig. 5, 1.2.3,*)^ edged with long setae, with two setae twice as long 

 as the others arising from the 4th lobe; from this 4-lobed basal joint or 

 coxopodite arise two appendages, the anterior (exopodite, ex), small, 

 1-jointed; the posterior (endopodite, en), 2-jointed, the end of the second 

 joint carrying above 5 long, spreading, stout, slender setae. This two- 

 jointed appendage Claus considers as representing the stock of a palpus. 



This pair of maxillae are quite unlike those of Decapods {Mysis, etc.), 

 as well as those of the Phyllopods, and appear to be another diagnostic 

 feature of the order. 



The absence of any maxillipedes, or of any rudiments of them, either 

 in the adult or in the embryo, is a negative character of a good deal of 

 importance when we regard the affinities of the group to the Decapods, 

 or the zoea-form of the same order, where two {Macrura) and three {Bra- 

 chyura) pairs of maxdlipedes are i)resent, there being three pairs in the 

 adult Decapod. 



The eight pairs of Phyllopodiform thoracic feet (Plate XXXVII, fig. 3). — 

 The maxillae are directly succeeded by eight pairs of leaf-like thoracic 

 feet, the maxillipedes not being present. The feet all repeat each other 

 in form, and a description of the 3d or 4th pair will answer for the 1st 

 as well as the last. The leg (Fig. 3, 3d or 4th pair) consists of a broad, 

 thin, six-jointed appendage, the endopodite {en), which is fringed with 

 very long delicate setae, those arising from the terminal joint being cil- 

 iated; while a second series of fine stilf setae arise obliquely from the 

 edge. To the second joint of the endopodite are appended a distal 

 or lower very broad thin gill, not quite twice as long as broad, and 

 which reaches to the end of the endopodite, while situated more exter- 

 nally is a double broad large lobe which corresponds to the exite or fla- 

 bellum of the Phyllopod foot, this flabellum being as long as the entire 

 endopodite, but not quite so broad as the gill. The distal portion of the 

 flabellum is more pointed than the proximal, and, as will be seen by re- 

 ferring to the figure, is more actively engaged in the process of respira- 

 tion. The figure shows by the dotted lines of parenchymatous matter 



1 Compare G. O. Sars. MonograpM over Mysider, 1870; PI. I, fig. 8. Claus states 

 tliat the large palpus is very similar to that of many Amphipoda, but apparently 

 overlooks tlie still closer resemblance to that of Mysis. 



"Claus draws attention to the position of this foot as compared with the 2d max- 

 illae (putzfuss) of the Ostracoda. 



