108 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
maxilla of Orchesella, Japyx (Meinert, ’65, Taf. XIV., Figur 8) and 
doubtless Campodea. More important, however, is the fact that the 
tendon of Scolopendrella is comparable with the mandibular retractor 
(cf. Latzel, 84, Taf. 1, Figur 5, «, and Meinert, ’65, Taf. XIV., Figuren 
5, 15, f,, flecor) of Campodea and Japyx, and may be homologous with it. 
It can be easily understood that, if the terminal lobes in Scolopendrella 
became immovable by solidification in the mandible, the adductors of 
those lobes would then serve as retractors of the entire mandible, as in 
Campodea and Japyx. 
Grassi (’86*, pp. 15-16, Tav. II., Figure 2, 5) supplements Latzel’s 
account of Scolopendrella by saying that no true cardo is present, and 
that the mandible is capable of lateral movements only. 
Packard (83°, p. 198) says, “The so-called mandibles of the Myrio- 
pods are the morphological equivalents of those of insects, but structur- 
ally they are not homologous with them, but rather resemble the lacinia 
of the hexapodous maxilla.’ With the last assertion I do not agree. 
The mandibles of the more generalized Diplopods are in detail strikingly 
like those of Scolopendrella (Latzel, ’g4, Taf. I, Figur 5); for example, 
those of Polyzonium (Latzel, ’84, Taf. XVI., Figur 203), in which the 
only fundamental difference is the presence of a cardo in Polyzonium, the 
stipes, galea, lacinia, and tendon being essentially as in Scolopendrella. 
The mandible, or protomala (Metschnikoff, 75), of Polyzonium does, in- 
deed, resemble, not the lacinia, but the entire first maxilla of Thysanura 
and Collembola. The similarity, however, should not be mistaken for 
homology ; it rather serves to emphasize the structural agreement of 
mandibles and maxille,—an agreement which gradually becomes ob- 
scure in the insect series through the progressive solidification of the 
mandible, but may nevertheless be traced, as I have shown, from Diplo- 
podaand Symphyla, through Campodea and Japyx, Machilis and Lepisma, 
to the more generalized Orthoptera ; thus the differences between the 
mandibles of Diplopods and Insects are not so great as Packard has 
affirmed (’98, p. 12). 
The most that is known about the development of Diplopod mouth- 
parts we owe to Metschnikoff (’74), who represents only two pairs of 
oral fundaments, designated ‘‘ mandibles ” and “labium.” Although this 
conclusion is also reached by vom Rath (’86), I would not infer with 
Packard (’83°, p. 199) that there can be only two pairs of oral appen- 
dages, but would suggest that embryological studies upon the mouth- 
parts of other Diplopoda may, perhaps, show more. 
The mandibles, or protomale, of Chilopoda are generally recognized as 
