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on the bottom of the inverted dish. The whole was then covered with 

 sterilized earth somewhat above the level of the upper edge of the 

 cask. A clean glass jar (I used ordinary finger-bowls) was then in- 

 verted over the whole. A few drops of kreosote were sometimes 

 scattered over the vaulted inner face of the glass jar. — The cask 

 was then ready either to be exposed to the direct sunlight or to be 

 heated only by diffused heat in the shade: which course was adopted 

 depended on the depth in which the eggs were placed inside the cask. 



As to the operations on the eggs themselves: the first necessary 

 condition was that the eggs should be those just deposited. 

 This is very necessary, as in Reptilian eggs a little time after their 

 deposition the white disappears from over the blastoderm — a fact 

 attended and indicated by the shell becoming white over the area — 

 and the blastoderm becomes attached to the internal face of the shell. 

 After this adhesion, it becomes almost impossible to detach the shell 

 from the blastoderm without rupturing the latter. Fortunately, I have 

 a practically unlimited command of freshly laid eggs in the turtle- farm 

 of Mr. Hattori to whom I am under greatest obligation for kindley 

 and cheerfully acceding to my numerous demands on his good nature. 



A freshly laid egg was carefully wiped with a piece of cloth soaked 

 with carbolic acid and then placed on a wax box. Although the blasto- 

 derm comes in this position always to be on the upper pole, I made 

 the point of having it in the identical position which it had when de- 

 posited by the tortoises in the ground, so that there should be as 

 little disturbances as possible in handling it. I then carefully cut 

 out by a pair of sterilized scissors a piece from the upper pole of 

 the shell and exposed the blastoderm. Sometimes, I did no injury 

 to the blastoderm, but on most occasions, made some sort of operation 

 on it. In doing this, a glass rod was drawn out to a fine point every 

 time, and with it I injured any part of the blastoderm that I liked. 

 These operations were not very difficult and with a little practice neat 

 clean openings large or small could be made at any desired point. 

 As there is only a large liquid space under the blastoderm, this liquid 

 probably oozes out on the upper surface of the blastoderm, but no 

 visible extra-ovale is formed as in Amphibia. This is a great 

 disadvantage in the experimental study of these eggs. 



In the earliest part of the season eggs with exposed blastoderms 

 were placed in the casks, and to my amazement, one egg produced 

 an embryo with two mesoblastic somites and with some other remar- 

 kable features which will need a most careful study. In this egg, the 

 white and the yolk had shrunk away and the conditions must have 



