No. 3-] THE EMBRYOLOGY OF A TERMITE. 549 



the yolk, into which some of the extra-embryonal membrane is 

 dragged down. (See my Text-Figure 2.) 



Comparing the diagrammatic text-figures here copied, — one, 

 Fig. I, after Heathcote (31), Fig. 14, showing the doubling-up 

 of the myriopod (Julus) embryo, and another. Fig. 2, after 

 Heymons (15), for Lepisma, — we find the thick germ-band in 

 each case enclosing a cavity. In the myriopod ^gg the two 

 ends of the embryo are on the surface, and there pass into 

 the thin extra-embryonal membrane. In the Lepisma tgg the 

 embryo lies more internally. Except for this, there is no essen- 

 tial difference apparent in the relations of the extra-embryonal 

 blastoderm to the embryo or in the nature of the open cavity. 

 Compare these two figures with the third text-figure of the 

 Termite, at a stage before the closure of the amniotic cavity, 

 and with the fourth figure of the closed amniotic cavity of the 

 Termite. (All eggs are represented as spherical for better 

 comparison.) 



Does the so-called amniotic cavity of Lepisma constitute any 

 nearer approach to the true amniotic cavity than the one pre- 

 viously found between the " doubled-up " body of the myriopod 

 embryo .-' I think not, without a further and more convincing 

 series of figures of some stages in the formation of the so-called 

 amnion, which would prove it to be any more truly an amnion 

 than the part of the blastoderm external to the embryonic band 

 of the myriopod, or in any way different from this, except in 

 being pulled down into the yolk. 



Instead of being an important intermediate stage between 

 the phenomenon exhibited by the myriopod embryo and the 

 formation of a true amnion, and amniotic cavity, in the winged 

 insects, there is nothing in the figures (nor does the single 

 descriptive paragraph convince without further figures) to give 

 reasonable grounds for the claim that there is any such differ- 

 ence between the phenomenon exhibited by the myriopod and 

 that shown by Heymons for Lepisma. 



The gap between the open cavity in the doubled-up myriopod 

 embryo and the true, closed amniotic cavity of winged insects, 

 seems just as wide as before Lepisma was studied from this 

 standpoint ; except in as far as the apterygota have been 



