68 



MYRIAPODA 



The first appearance of the mouth appendages has been 

 ah-eady mentioned, and these are shown in Fig. 43, where the 



""^^IftP^"- 



s.s. 



N-.C. 



Tr.I. 



Fig. 42,— G', gut; 3Mp.T, Malpighian tube ; X.C, nerve cord; Tr.I, deep invagiua- 

 tiou by which the tracheae are formed ; 2/.s, yolk spherules still present ; L, first 

 appearance of legs ; S.S, part of mesoblast. (Heathcote, Post. Emb. Dev. of 

 Jidus terresiris.) 



small stumps that later on change to jaws are shown. The 

 figure shows the head of a young Chilog- 

 nath seen from the lower side, and the 

 second pair of stumps fuse together 

 later on and produce the broad plate 

 already mentioned as the characteristic 

 mouth appendage of the Order. 



After the animal is hatched it has 

 still, in the case of most Myriapods 



''\erd^t^f;Lnfrj:'.':! (^^^^^ ^-^^^^^ ^-^ ^ot hatched with an 

 rcsfrw .■ ^TO. )«, rudimentary the segments Complete), to undergo a 

 mouth pilte'™a™a™en°ua7 farther development, and in particular 

 the eyes are still unformed. The pro- 

 cess of development of the eye has only been followed out as yet 

 in the Chilognatha, and in only one form, Julus, and is so curious 

 that a short account may be of interest here. The develop- 

 ment of the eye begins (in Julus) on the fourth day after hatch- 

 ing, and continues until the animal is full grown. A single 



