It is interesting to observe that, as in spiders, the 

 legs are full of yolk, only the tips being free. The yolk 

 seems to get pushed backwards during the growth of the 

 legs pari passu with the growth of the muscles and 

 nerves. Neither the median nor the lateral eyes have yet 

 begun to appear, nor are the lungs, heart, coxal gland, 

 lateral organs, or alimentary canal in any degree traceable. 



It is in the yolk that the chief peculiarity is to be 

 seen. The neighbouring eggs have, through pressure, 

 caused a deep semi-circular impression on one side of the 

 embryo, and at the same time caused it to develop in 

 two halves. The pressure has also influenced the yolk, 

 causing several of the yolk-spherules to amalgamate and 

 to form a mass without any regular shape. The appear- 

 ance of this fusion necessitates the conclusion that the 

 living yolk particles were of a fatty nature, and that 

 they were suspended in a watery lymph, forming a kind 

 of emulsion. 



Stage IV. 



The next stage which I possess is only a little more 

 mature than the one just described. The reversion of the 

 embryo has taken place long ago, the cephalothorax being 

 separated from the abdomen. The extremities are much 

 further advanced than those of the third stage and, except at 

 their bases, are devoid of yolk. In surface views one 

 sees the Anlage of the brain as two white spots at the 

 front end of the cephalothorax. On the sides may be 

 seen, at the base of the fourth pair of extremities, a 

 horseshoe shape excrescence; this is the lateral orgau, 

 first described by Laurie as occurring in Phrynus it is 

 always covered by a shred of some dark substance. 



The joints of the legs can already be distinguished, 

 the embryo at this stage greatly resembling the one 

 given in the drawing (figs, 1 and la) less the eyes, and 

 with a much smaller amount of brain. 



There are six pairs of extremities to be observed. 

 The first pair, the chelicerse, now lie before and on both 

 sides of the mouth, and under the fold which carries the 



