6 
-ackard.] 200 (June 16, 
dibles, and like the primitive embryonic mouth-appendages of any arthro- 
pod. Hence the differentiations of parts and coalescence of the two limbs, 
while closely resembling that of the labium or second maxille of hexapods, 
really occur in Myriopods in a different pair of appendages, 7. ¢., the second 
instead of the third pair. Hence the parts called labium (many authors) 
in Myriopods are really homologous with the first maxillee of insects ; and 
they should, to prevent misconception, receive a distinctive name (deuto- 
male). With the aid, then, of embryology we have arrived at a clearer 
conception of the homologies of the second pair of mouth-appendages in 
the Chilognaths. It formsa broad flat plate, becoming the floor df the 
mouth, and forming an under lip; it is differentiated into two sets of broad 
plates, an outer and inner stipes; the outer stipes (stipes ewterior) bears at 
the free edge two movable toothed appendages, which may be designated 
as the inner and outer malellw. The inner stipes (stipes interior), are 
united firmly, and are supported behind by what Meinert designates as the 
lamina labialis, behind which is a curved, broad sclerite called by Meinert, 
the hypostoma ; a rather unfortunate name, as it has been used by Meigen 
and Bouché for the clypeus of Diptera. Differentiated from the front edge 
of the inner stipes, is a piece usually separated by suture, which, as we un- 
derstand it, is the stelus linguahs of Meinert ; it is our malulella. A. median 
portion of the deutomala has been apparently overlooked by authors ; it is 
our labiella (fig. 2), and corresponds in a degree to the lingua of 
hexapods ; it is a minute rounded piece situated between the malulelle ; 
in Julus minute and single; in the Lysiopetalide much larger, and divided 
into a large anterior, and a much smaller posterior crescent-shaped part ; 
it is supported by two long cylindrical divaricating styles. 
It thus appears that the head of Chilognaths bears but three pairs of ap- 
pendages, viz., the antenns, and the mouth-appendages, the proto and 
deutomale. Without doubt the Chilognaths, as proved by their embry- 
ology and morphology, and their close relationship with the Pauropoda, the 
simplest. Myriopods, represent the primary form of the Myriopods, while 
the Chilopods are a secondary, less primitive group. Paleontology appa- 
rently supports this view. We may now turn to the structure of the head 
of Chilopod Myriopoda, which has been fully described by Newport,* and 
also by Meinert.+ 
Having already briefly described the morphology of the epicranium or 
antennal segment of Chilopods, with the labrum and ‘‘ mandibles ’’ (pro- 
tomale = ‘‘true maxille’’ of Newport), which are close homologues of 
those of diplopod myriopods, we may next take upthe second pair of mouth- 
appendages, which are the morphological equivalents of the so-called la- 
bium of Chilognaths. These, as seen in Scolopendra, are very different 
* Monograph of the class Myriopoda, Order Chilopoda; with Observations on 
the general arrangement of the Articulata, By George Newport, Trans. Linn. 
Soc., xix, p. 287. 
+Myriapoda Mussei Hauniensis Bidrag til Myriapodernes Morphologi og 
Systematik ved Fr. Meinert, Af Naturhistorisk Tidsskrift, 3 R. 7 B., 1871. 
