FOLSOM: MOUTH-PARTS OF ANURIDA MARITIMA. 12 
they are somewhat larger, and ventral or lateral surface views of the germ 
band (Plate 2, Figures 9, 10 ; Plate 3, Figure 11) disclose a distinct lateral 
lobe, the palpus (p/p.), which is larger than that of the first maxilla. 
A second maxilla, as dissected out at this stage, is shown in Figure 18 
(Plate 3). Transections of the germ band (Plate 3, Figure 14) show 
the palpus to be an outfolding of the antero-lateral face of the primary 
maxillary evagination, just as in the case of the first maxilla. 
At this stage (Plate 2, Figures 9, 10) there appears near the mandibles 
a lateral evagination (pl. or.) of the germ band, destined to form the 
side of the face; this fold grows backward until it involves the base of 
the second maxilla of the same side, and the internal cavities of the two 
folds become one. In Stage 4 (Figure 4; Plate 3, Figure 19) it has 
already involved the base of the second maxilla; the apex of the maxilla, 
however, is still free from the fold, and the palpus (Plate 3, Figure 12, 
plp.) is as large as that of the first maxilla. 
At Stage 5 the second maxille (Figure 5; Plate 3, Figure 20, mz.*) 
are long, oval in cross-section, and project at right angles to the germ 
band; the antero-lateral region of the base is confluent with the mouth- 
fold (Figure 21). At this period all trace of the second maxillary palpus 
becomes lost ; it has not become involved in the mouth-fold, which is 
still restricted to the base of the maxilla, but has been rapidly resorbed 
and appears at last as indicated in Figure 20. In the next stage (6) 
the second maxille (Figure 6) converge toward the median plane like 
the other pairs of oral organs, and similarly swing forward. 
At Stage 7 (Plate 2, Figure 7) the second maxillze and mouth-folds 
are quite confluent (Plate 5, Figures 30, 34), but the anterior part of 
each maxilla is still distinguishable as a swollen lobe, or less flattened 
region (Plate 4, Figure 24, /ab.). The bases of the second maxille, 
although widely separated in Stage 5 (Plate 3, Figure 21, mzx.”), sub- 
sequently spread toward the median plane, become thinner, and gradually 
form a single plate; the median sinus between them shortens until the 
condition shown in Plate 5, Figure 29 (/ad.) is attained. The union of 
the second maxille with each other is not a simple contact and_fusion 
resulting in a median suture ; but a confluence of the cavities of the two 
maxille occurs and progresses forward (7. ¢., distally), ceasing, however, 
before obliterating the median sinus, which remains in the adult (Plate 
7, Figures 43, 45, swt. m.and swl.). Although the finished labium bears 
a median ventral groove, the groove does not indicate the fusion of the 
fundaments; at Stage 7, when the labial plate is complete, no trace 
exists of the groove, which is formed in a later stage. A comparison of 
