FOLSOM: MOUTH-PARTS OF ANURIDA MARITIMA. 107 
“ The mandibles [of Caloptenus] remain single-lobed,” and both Wheeler 
(’93) and Heymons (’95") represent them as simple papille in all fami- 
lies of Orthoptera. It may at least be said, however, that the mandibles 
of Collembola and Thysanura are certainly homologous in their entirety 
with those of Orthoptera, and hence of all other insects. 
It is an interesting fact that Heymons (96, Taf. II., Figur 29) dis- 
tinctly represents mandibular palpi for the larva of Ephemera, 
condition ; indeed, Packard (’98, p. 61) terms this appendage of nymphal 
Ephemerids a “lacinia-like” process, although Heymons states (p. 21) 
that it is lateral in position, and so figures it. 
What embryological evidence there is, then, confirms the view based 
upon anatomical data, that “the mandibles are primarily three-lobed 
appendages like the maxillz ” (Packard, ’98, p. 61). 
Turning now to the Myriopoda, the Symphyla, represented by the 
single genus Scolopendrella, show marked affinities with Campodea, as 
is well known. I wish here to emphasize especially the correspondences 
a rare 
between the mouth-parts of the two genera, which have never been 
carefully compared in these respects. 
Latzel (’84, p. 8, Taf. I., Figur 5) describes the mandibles of Scolo- 
pendrella as follows : ‘‘ Die Oberkiefer bestehen jederseits aus einer fast 
horizontal gelagerten, trapezoidalen Chitinplatte, welche am End- oder 
Kaurande durch eine mittlere Einbuchtung in zwei Partien abgetheilt 
erscheint, von denen die vordere in vier kriftige, die hintere in vier bis 
fiinf kleinere Zailnchen eingeschnitten ist. Eingelenkt sind diese Kie- 
ferplatten mit dem hinteren und dusseren Eck in eine zwischen Kopf- 
decke und Unterseite eingelagerte seitliche Lamina, welche einige 
Aehnlichkeit hat mit der Wange der Insecten und die von Menge als 
Theil (Stamm) der Oberkiefer aufgefasst wird. Am inneren Hintereck 
jeder der beiden Oberkieferplatten entspringt eine sehr kriaftige Sehne, 
die in eine betrachtliche Anzahl von Muskelbiindeln auslauft, welche sich 
unten am Kopfrahmen inseriren.” 
The mandibles of Scolopendrella therefore resemble those of Cam- 
podea rather than those of any other insect, in that they are hollow, 
with a basal (stipal) part articulated to the skull, and a head separated 
transversely from the fulcrum. The head consists of two primary lobes 
(galea and lacinia) as in Campodea, but both are movable by muscles, 
whereas in Campodea the lacinia alone is articulated, and even this no 
longer has muscular attachments. Thetendon and muscles which move 
the lacinia of Scolopendrella are exactly similar in position and function 
to the “chitinous rod” and muscles which adduct the head of the first 
