SEGMENTATION AND PHYLOGENY OF ARTHROPODA. 491 
EXPLANATION OF PLATE 28, 
Illustrating Professor Carpenter’s paper on “ Notes on the 
Segmentation and Phylogeny of the Arthropoda, with an 
Account of the Maxille in Polyxenus lagurus.” 
REFERENCE LETTERS. 
Ji. Tongue or hypopharynx. Ja. Labium, Ja’. Basal membrane of labium. 
mz. Maxilla, basal sclerite. ma. lod. Maxilla, lobe. ms. p. Maxilla, palp. 
mal. Maxillula. ji. Flagellate process. m. add. Adductor muscle. m. add. 
Abductor muscle. md. Tip of mandible. ddr. Edge of labrum. 
Fic. 1.—External (posterior) view of the maxille of Polyxenus lagurus. 
The left maxilla has been removed to show the maxillula and tongue. 
Fic. 2.—Internal (anterior) view of left maxillula and tongue cf Poly- 
xenus lagurus. The central region of the tongue only is shown. 
Fic. 3.—Left maxillula of Polyxenus isolated ; external (posterior) view. 
Fic. 4.—Right maxilla, maxillula and apex of tongue; ventral view. 
Fic. 5.—Semi-diagrammatic lateral view, showing relations of maxillula, 
maxilla, and labium ; the palp is displaced and truncated. 
All figures are magnified 285 diameters. 
