wards the surface, just as they do in spiders. The pressure 

 of the two membranes also points to a resemblance with 

 most of the other orders of Arachnids, whose eggs are 

 also regularly enclosed in two membranes. 



The yolk itself consists of at least two different kinds 

 of yolk elements. The first of these tinges very freely 

 with eosin, and is not influenced by hematoxylin. It 

 consists of larger and smaller spherules measuring between 

 •09 mm. and -02 mm.; they form the greater bulk of the 

 yolk. The other yolk element is much more irregular in 

 shape, and helps to fill the spaces between the spherules 

 of the element first described, to which it adheres, thus 

 becoming crescent-shaped in cuts, and in reality forming 

 convex-concave lenses. It also differs in tinction from the 

 first described kind of yolk, staining both with hsema- 

 toxylin and eosin to a light purple. 



The size of these yolk- bodies varies between 036 mm. 

 and *05 mm. The distribution of the yolk elements does 

 not seem to follow any definite rule, unless, perhaps, that 

 the yolk elements last described are more numerous in 

 the interior of the egg. I shall not again refer to the 

 yolk or to the membranes, excepting where I have to 

 point out a change in them. 



Stage II. 



The next stage at my disposal is only a little further 

 developed than the one just described. It is derived 

 from a batch of eggs which are all at about the same 

 stage of development. 



Surface views of these eggs show that the blastoderm 

 is already formed. It appears as a long white ribbon 

 covering about one third of the surface of the egg in length 

 and one sixth in breadth. At one end the white patch 

 seems much thicker, being more opaque in reflected light. 

 The blastoderm is not of the same breadth throughout 

 its length, but is somewhat narrower in the middle, and 

 rounds out at both ends. The margins are not distinct 

 or abrupt, but gradually fade away until at last they 

 become invisible. 



