FOLSOM: MOUTH-PARTS OF ANURIDA MARITIMA. 119 



lateral " superlingUce," which have been usually overlooked or disre- 

 garded in Pterygote insects, represent a distinct though reduced somite, 

 as confirmed by the presence of a primitive ganglion. The superlinguai 

 are homologous with the first maxillae of Malacostraca, and are probably 

 represented in Diplopoda. 



The lingua of insects is homologous with the Crustacean hypopharynx 

 and probably with the median constituent of the gnathochilarium of 

 Diplopoda. 



Maxillae. 



The fundaments of the " first maxilliB " appear next after those of the 

 mandibles, and at Stage 1 (Plate 1, Figure 1 ; Plate 2, Figures 8, 8a, 

 vix.^) are a pair of small hemispherical papillse, similar to those of the 

 mandibles. At Stage 3 they are longer than the mandibles and must 

 consequently have lengthened faster. As seen in transections of the 

 germ band, the maxilla is at first a simple ectodermal evagination, api- 

 cally rounded, but at Stage 3 (Plate 3, Figure 15) the apex is flattened, 

 and a lateral lobe, the beginning of the palp, has appeared ; this lobe is 

 also seen in the ventral aspect of the germ band (Plate 3, Figure 11, 

 pip.) as well as in the lateral views (Plate 2, Figures 9, 10). The pos- 

 terior aspect of the left first maxilla when dissected out is given in 

 Plate 3, Figure 17. 



At Stage 4 (Plate 3, Figures 12, 19) the maxilla has elongated con- 

 siderably and its base is covered by the lateral fold of the germ band 

 (Plate 3, Figure 1 9, pli. or.), as already mentioned. In the following stage 

 (Plate 3, Figures 20, 21, mx}) the maxilla and palpus, though longer, 

 are more nearly concealed by the lateral fold. The form of the maxilla 

 with its palpus at this stage is shown in Figure 22, which was drawn 

 from a dissection ; the base of the maxillary fundament is already 

 oblique, precisely as described for the mandibles, and the first maxillee 

 have begun to converge toward the median plane. It is to be remem- 

 bered that the palpus is here a secondary lobe of the primary 

 fundament. 



At Stage 7 (Plate 4, Figure 24 ; Plate 5, Figures 29, 30, mx}) the 

 first maxillae, now covered by the lateral folds, have swung forward 

 through an angle of almost ninety degrees (Figure 24), like the man- 

 dibles. Claypole ('98, p. 263) states that " a flexure of the embryo be- 

 gins that results in crowding the mouth-parts together to form a definite 

 head," but such a purely mechanical interpretation will not serve, be- 



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