FOLSOM: MOUTH-PARTS OF ANURIDA MARITIMA. oF 
In Stage 6 (Plate 1, Figure 6, at.) there is clearly indicated a fourth 
antennal segment, which in Stage 7 (Plate 2, Figure 7; Plate 4, Figure 
24, at.) becomes more distinct. At this time the antenne are long and 
stout, and occupy a position still farther forward than before. 
At hatching (Plate 6, Figure 41) they are pre-oral, more slender, dis- 
tinctly segmented, and clothed with sete. 
Elongation of the antenne occurs throughout their entire length, 
judging from the number of cells in longitudinal alignment on the same 
segment at different stages of growth, and also from the frequency of 
karyokinesis in different parts of the appendage. Growth is more rapid, 
however, in the apical region, from which the segments are successively 
constricted. In all the oral fundameuts, in fact, growth was inferred to 
be most rapid at the apex, although likewise occurring throughout the 
rest of the ectodermal layer. At the apex itself— and these remarks 
upply equally well to the legs—the hypodermal cells are larger and 
more turgid than elsewhere, projecting as minute lobes from the surface. 
The chromosomes are very small, but frequently so arranged as strongly 
to suggest mitotic division. 
At Stage 5 (Plate 4, Figure 28, dew’ceb.) an antennary ganglion sup- 
plying the antennal nerves, becomes evident, but finally fuses with the 
first and third ganglia, between which it lies, to form the supracesophageal 
ganglionic mass. 
In Thysanura the antennz develop essentially as I have described for 
Collembola, being likewise at first post-oral and subsequently pre-oral, as 
Uzel (98) has shown for Campodea and Heymons (’97*) for Lepisma. 
Such a migration of the antennz is, however, not peculiar to Aptery- 
gota, but is characteristic of all insects. 
Among Diplopoda but a single pair of antennal fundaments occurs 
(Heymons, ’97°, p. 7, Figur 2, Glomeris). Judging from their position 
in relation to the mouth, they are equivalent to the antennz of Chilo- 
poda, among which Heymons (’97°, p. 4, Figur 1, Scolopendra) has 
discovered two pairs of antennal fundaments. The pre-antennal rudi- 
ments in Chilopoda appear to represent the antenne of insects and the 
antennules of Crustacea, the second pair to be equivalent to the inter- 
calary appendages of insects and the antenne of Diplopods and of 
Crustacea. 
It can scarcely be doubted, in view of the researches of Viallanes (87), 
that the antenne of insects are homologous with the antennules of Crus- 
tacea. In the author’s words (’87, p. 105): “ Voyons maintenant le 
deuxiéme renflement cérébral du Crustacé décapode. II est formé d’une 
