en 
A.—Mazxilla of lobster with its five lobes (1-5) corresponding to the endites of the Phyllopod 
thoracic limb. 
B.—Section through the thorax of Apus. en, 1-6, the six endites; ex, exopodal or respira- 
tory portion of the limb; c, carapace; ht, heart; int, intestine; ng, ganglion. 
? 
0) 
Wy, 
a 
‘B 
es) 
rn 
i 
an 
Mee 
C.—Partly diagrammatic section through the thorax of Nebalia. en, the pascaer Meaas 
endopodite; ex, exital portion or gill (above irregularly dotted) and flabellum below with rows 
of dots; c, carapace. 5 é 
D.—Actual section through the abdomen of Limulus; ¢, carapace; ht, heart; int, intestine; 
ng, ganglia ear a being the same as in C); en, axial-jointed endopodite; ex, exital or 
respiratory portion bearing the gill-lamelle; the outer division (ez) homologous with the 
exopodal portion of the phyllopod and phyllocaridan appendage. 
HOMOLOGIES OF THE CRUSTACEAN AND LIMULUS LIMBS. 
[To face page 270.} 
