VI 



ANTENNATA— MOUTH PARTS 



447 



oc 



Myriapoda. 



Symphyla.— Moil til parts for chewing. Upper lip, mandibles, and 1 pair of 

 maxilljB with only 1 masticatory ridge and rudimentary feeler. The Paurojpoda 

 have similar month parts also weakly 

 developed. The mouth parts of both 

 groups require further investigation. 

 Chilopoda (Fig. 304).— The mouth 

 parts, apart from the upper lip and jng - 

 the hypopharynx which belongs to nii^ 

 the lower oesophageal wall, consist of 



the typical limbs, mandibles, anterior i as '^MX ■ il^ M -M—nf 



and posterior maxillae. The anterior ^ »'=si*^'vSscl^ / /^ii^jsW J^ I 



pair of maxilloe has well developed ,f^,j_ 

 masticatory ridges, but has no feeler 

 or only a rudimentary one. The 

 feelers are well developed on the 2d 

 pair of maxillae, but the masticatory 

 ridges are wanting. The basal por- 

 tions of these maxiUie are sometimes ^ Fig. 304.-Litlio6ius validus. The head from 

 , ^- f ^ below after removal of the maxillipedes (after Latzel). 



separate, sometimes fused. ^_ iaitennse ; sk, frontal portion of the cephalic shield ; 



Diplopoda. — The mouth parts are oc, grouped ocelli ; pi, feeler of lower lip or of the 2d 

 here complicated and difficult to ex- pair of maxiUse ; stl, stems of the same fused in the 

 plain The powerful upper jaw is ™'l<lle 1™^ ; s'™' ^t^™^ °' l*^* P™ °f maxilte ; me, mi, 

 followed by the lower lip (gnatho- outer and inner ridges of the same, 

 chilarium. Fig. 305). This lower lip is said by some observers to consist of only 

 1 pair of maxillse. Others explain the pieces represented in the figure in such a way 



that the paired halves of the middle 

 piece, each of which is provided with 

 a masticatory ridge, correspond with 

 the stem pieces of the posterior 

 maxillie (lower lip), and the 2 lateral 

 pieces each provided with 2 masti- 

 catory ridges with the stem portions 

 of the anterior maxillfe, the palps 

 being absent. Although this last 

 view, which rests upon analogous 

 modification of the 2 pairs of maxillte 

 in certain beetle larvae (Slateridce), 

 is preferable from the point of view 

 of comparative anatomy, it is not 

 yet quite certainly established. The 

 developmental history, as far as it is 

 as yet known, seems rather to support 

 the first view, since the mandibles 

 and the gnathochilarium of the 

 Fig. 305.-The Gnathoohilanum of Lysiopetalum jlipZo^joda are said to come from the 

 cannatum (Biplopoda, after v. Rath), mxi, Stem of -,. , f „ ■ r ^ ^ » 

 the anterior ; mx,. of the posterior maxilte (?) ; me and ™diments of 2 pairs of feet. A eom- 

 mi, outer and inner masticatory ridges of the anterior parison of the mouth parts of the 

 maxill£e ; m, masticatory ridge of the posterior maxillae Myriapoda on a new ontogenetic 

 (lower lip). basis is urgently needed. 



Hezapoda. 

 Apterygota. — The mouth parts of the Apterygota are adapted for mastication 



mx] 



