FOLSOM: MOUTH-PARTS OF ANURIDA MARITIMA., 147 
The antenne of Apterygota evaginate from the posterior boundaries 
of the procephalic lobes, and therefore agree with those of Pterygota in 
this respect. In both groups the antenne are at first post-oral and sub- 
sequently pre-oral in position. 
The deutocerebrum of insects is homologous with that of Crustacea, 
and the antenne of Hexapoda are equivalent to the antennules of 
Crustacea and the embryonic preeantennee of Chilopoda. 
Premandibular, or intercalary, appendages exist in the embryo of 
Anurida, and appear to be represented even in the adults of several 
Apterygote genera. The tritocerebrum of Apterygota is homologous 
with that of Orthoptera and decapod Crustacea, and the rudimentary 
premandibular appendages of Collembola and Thysanura represent the 
second antennz of decapod Crustacea and probably the antenn of 
Diplopoda and Chilopoda. A distinct primitive ganglion occurs in the 
intercalary segment of Anurida, therefore the segment must be regarded 
as one of the primary head-segments. 
The mandibles of Apterygota develop from a pair of simple papille, 
the bases of which become oblique. No trace of lobation occurs except 
in Campodea. The mandibles of Collembola and Thysanura are homo- 
dynamous with the maxille and homologous with the mandibles of 
Pterygota, Scolopendrella, Crustacea, and probably Diplopoda and 
Chilopoda. 
The “hypopharynx” in Apterygota is a compound structure consist- 
ing of two dorsal “superlingue,” —as I have called them, — which 
develop from a pair of papillee between the mandibular and first maxil- 
lary segments, and also a ventral lingua, which originates independently 
as a median unpaired evagination on the first maxillary segment. The 
two chitinous “lingual stalks,” which are most highly developed among 
Apterygota, arise in superficial grooves of the ectoderm. The hypo- 
pharynx of Apterygota is undoubtedly homologous with that of Ptery- 
gota; although, in the latter group, the lingua and superlinguze become 
united together and the lingual stalks become rudimentary. In Anurida 
a distinct neuromere exists for the “ superlingue ;” therefore it is neces- 
sary to recognize the superlingual segment as equivalent in morphologi- 
cal value to the other primary somites. The superlingue are homologous 
with the first maxillze of Malacostraca and Chilopoda and are anatomi- 
cally represented in the labial plate of Diplopoda. In order to avoid 
confusion, the terms “ paraglosse ” and “ligula” should not be applied 
to the constituents of the hypopharynx, but are better restricted to the 
labium of insects. The lingua of Hexapoda is equivalent to the Crusta- 
