DEVELOPMENT OP PERIPATUS NOV^-ZBALANDT^. 263 



On the Development of Peripatus 

 Novee-ZealandisD. 



By 



liillan Sbeldon, 



Bathurst Student, Newnliam College, Cambridge. 



With Plates XXVII and XXVIII. 



In January last, through the kindness of Mr. Sedgwick, 

 I received another supply of Peripatus novse-zealandise. 



As before, they arrived in the living condition, and the eggs 

 •were removed from the uterus immediately after the animal 

 had been killed with chloroform. 



The proportion of males was considerably larger than on 

 previous occasions, being twenty-two out of a total of forty- 

 nine. There were nine smallish females which contained no 

 embryos ; and in the remainder, which varied in size from 

 about three-quarters to two inches in length, the uteri were 

 filled with embryos. The number of embryos in a single 

 female varied considerably, the maximum being eighteen and 

 the minimum seven. 



Most of the embryos were preserved in corrosive sublimate 

 and glacial acetic acid used hot, but the best results were 

 obtained from some which were placed for six or seven hours 

 in a mixture consisting of equal parts of '5 per cent, chromic 

 acid and 2 per cent, acetic, and afterwards washed in alcohol. 

 In this method it is not necessary to prick the egg-shell before 

 the embryo is removed to alcohol. After this method of pre- 

 servation, which is that recommended by Hertwig for amphibian 



X 



