104 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
21. He also gives a figure (Taf. V., Figur 64) supporting his state- 
ment (p. 22) concerning the appearance of the mandibular segments: 
“ Ausserdem [collection of entoderm cells, etc. ] bemerkt man zwei Paar 
dunkler Stelle, welche an den Ecken eines gedachten Quadrats sich 
befinden. Das dem Dorsalorgane geniherte Paar dieser Blastodermver- 
dickungen (4/.) sind die getrennten Anlagen der Kopflappen, das zweite 
Paar (mds.) stellt die getrennten Anlagen des Mandibularsegmentes vor.” 
The eggs of Anurida at my disposal were either too old or too young to 
show the condition here described by Uzel, although I did find a stage 
in which three pairs of fundaments were present, the third pair being 
the first maxilla. The mandibles probably follow the procephalic lobes 
in appearance, as I have found all the stages necessary to indicate that 
the remaining paired appendages, except those of the superlingue, as I 
shall term them, appear successively from in front backward. 
Campodea is structurally nearest to the Collembola, and, thanks to 
Uzel (98, Taf. IIL, Figuren 35, 36; Taf. VI., Figuren 77-85), some- 
thing is known concerning the development of its mouth-parts. The 
mandibular fundaments of Campodea are simple papille, as in Collem- 
bola ; this simplicity distinguishes the Apterygota from the most gener- 
alized Pterygota, the Orthoptera, in which the fundaments are sometimes 
lobed. 
The finished mandible of Campodea is strikingly like that of the 
Collembola, and is, moreover, of great morphological interest, because 
the structural correspondence of the mandible with the maxilla of hexa- 
pods — obscure in almost all other insects —is here a matter of direct 
observation, not merely one of inference. The mandible of Campodea 
(Meinert, ’65, Taf. XIV., Figuren 15, 16; Nassonow, ’87, p. 33, Figur 
27) consists of a hollow fulerum (stipes) and a head, which is separated 
from the fulcrum by a transverse suture. The head is composed of two 
parts, — a large, toothed, immovable, outer lobe or galea, and a smaller, 
fringed, movable, inner lobe, representing the lacinia. 
Accepting the homologies with the first maxillee implied in these 
terms, the palpus remains to be accounted for. A mandibular palpus has 
never been found among adult insects, — the evidence given for one 
by Hollis (’72) being quite vague and inadequate. Although the de- 
tailed development of the mouth-parts of Campodea has never been 
followed, it is in this most generalized insect that one may most hope- 
fully look for a trace of a mandibular palpus, and we may safely predict 
that, if found, it will be a lateral, distal lobe of the stipal region, just as 
it is in the maxille of all insects. 
