300 



THE DEVELOPMENT 



Fig-. 200. 



jfc 11 



B 



(a 1 , c 1 , c 2 , c 3 , c 4 , c 5 ). A peculiarity of this 

 phase, not before noticeable, and which 

 is the forerunner of a remarkable change 

 in the relative position of front and back, 

 is evinced by the backward curvature 

 of the head (A;) so as to sink it inward 

 loward the centre of the yolk mass, (?/,) 

 and allow the tail (tl) to overlap it. 

 Not yet, though, are we permitted to 

 pronounce upon the special relations of this creature, since the 

 most that its jointed body teaches us is that it is an Articulate 

 animal; and, for all we can see, it may be a worm instead of 

 an insect. 



But in regard to the latter category, we do not remain long in 



doubt; for in a short time three pairs of 

 legs (fig. 201, e, /, g-) begin to develop 

 from the last three of the joints just 

 mentioned, and in front of them arise 

 four pairs of jointed appendages which 

 appertain to the head, and perform the 

 office of feelers, (,) and upper (b) and 

 lower (c, d) jaws. The presence of legs 

 determines the character of the embryo 

 as that of an Articulate which is higher in grade than the 

 worms, and their number, namely, three pairs, distinguishes it 



Fig. 200. The same as figs. 198, 199, in the third stage. 220 diam. k, the 

 head ; aft, the abdomen ; (I, the tail, overlapping k ; a 1 , the first joint of the body 

 after the head: c 1 , the second, and c 2 , the third joint of the same; c 3 , the first, 

 c 4 , the second, and c' 5 , the third joint of the thorax, from which the first, sec- 

 ond, and third pair of legs develop; ?', i 1 , the transverse furrows between the 

 segments ; y, 7/ 1 , the yolk. From Zaddach. 



Fig. 201. The same as figs. 198 to 200, in a further advanced stage. 220 

 diam. A profile view, k, the head ; f/ 1 , the first, d 5 , the fifth, and </ 10 , the tenth 

 joint of the abdomen; ?/, the bend of the tail; B, the forehead; a, the feelers; 

 b, the upper jaws; c, </, the under jaws; C 2 , the joint of the body from which d 

 arises; e,f, g, the first, second, and third pair of legs; ?/, the remains of the 

 yolk. From Zaddach. 



