224 



MYRIOPODA. 



(Fig. 109 B, a). The mouth, on the contrary, is said to appear 

 only at a later stage. It can be seen as an invagination between 

 the cephalic lobes when five segments have developed. 



It is difficult to ascertain from the descriptions given whether the oral 

 invagination lies in front of the antennae ; this is certainly indicated in Fig. 

 Ill of a Gcophilus embryo, while in other figures {e.g., Fig. 110) it is not 



i „ lXi IZ£:~ 



o/-- 



Figs. 110 and 111.— Two stages in the development of the germ-bauds of Geophilus ferrugineus, 

 unrolled (alter Sograff). a, anus ; at, antenna ; Id, cephalic lobes ; m, mouth ; md, mandi- 

 bles ; m.g, Malpighian vessels; mp, maxillipedes (or segment of the maxillipedes); mx 1 , 

 in : ... first and second maxillae (or segments of the same) ; nr, neural groove ; ol, upper lip ; 

 p, legs; p lt ?).,, segments of the first two pairs of legs; r, ventral longitudinal groove; 

 s, the lateral parts of the germ-bands which already show segmentation ; si, caudal lobe ; 

 ul, paired rudiment of the lower lip. 



evident. In this latter figure, which represents an earlier stage than Fig. Ill, 

 the antennae rather lie in front of the mouth, but another circumstance still 

 to be described in connection with the formation of the organs indicates that 

 the condition here resembles that in Peripalus, and that the antennae have 





