1 882.] Representing the order Phyllocarida. 873 



then we see that the diagnostic ordinal characters of the Phyllo- 

 carida have declared themselves. There are to be seen in Ne- 

 balia the large movable rostrum, the compressed pseudobivalvu- 

 lar carapace, the lack of maxillipedes, the eight pseudophyllopod 

 thoracic feet, and four pairs of abdominal feet, out of the six of the 

 adult. On the other hand, in Mysis of the same stage, the two 

 pairs of maxillipedes are well developed, and the six pairs of 

 remarkably long thoracic feet (the first pair modified maxillipedes) 

 are present. There is little to indicate that the Schizopods have 

 descended from a Nebalia-like form, but rather from some accel- 

 erated zoea form ; while, as we attempt in this essay to show, the 

 Phyllocarida have had no Decapod blood in them, so to speak, 

 but have descended by a separate line from Copepod-like ances- 

 tors, and culminated and even began to disappear before any 

 Malacostraca, at least in any numbers, appeared. 

 EXPLANATION OF PLATE XIII. 



Fig. i.—Nebali 



a £z>«Kroyer; female, muc 



h enlarged. 

















.'V'^'mu.!''-. 



fmaxUla-^ftomac 

















tea of the coxopodite 







; en, endopodite. 



" 6._(Omitt 







" 7. — Cercupoila or caudal stylets. 





" 8.— Portior 



1 through a ventral ganglion. 



minal segment. 





EXPLANATION OF PLATE XIV. 



Fig. \.—Nebaln 



ttifesKx. 9 ; 1 st antenna;! 



ettering as in PI. xir 













« 3 --Oneof 



the 3d or 4th pair of thoraci 











" 4 .-One°oi 



2d pair of abdi 



ret, retinaculum; e> 



« £325 



lir of abdominal 





« 6.-Sectior 







the stoma 







cle ; sh, s 







" 7-— Sectior 



1 through one of the coeca. 







EXPLANATION OF PLATE XV. 



" 6. — Embryo of Pseudomma about J 

 Figs. 1-5 copied from Metschnikoff. 



