246 SEA-SIDE STUDIES. 



times the division occurs in two unequal halves ;* sometimes in 

 three, or even four, unequal parts. I have even counted five. 

 The germ-mass may develop into one, two, three, or even 

 six embryos, -f aU of which are seen slowly rotatmg in the 

 same envelope ; and besides these, there may generally l;e 

 seen various masses of granules rotating with them, or diiveu 

 about within the envelope — which are probably fragments of 

 the germ-grass insufficient to form a separate embryo. This 

 multiplication of individuals from one egg, this production of 

 tmns, or triplings, is a constant fact, and may help the 

 general question of twin bu-ths. Very curious it is to watch 

 the increasing activity of the little embryos. At first theii" 

 rotation is scarcely perceptible ; after a whUe the long cilia 

 protruding from the shell are seen to wave vAi\\ more vigour, 

 and the animal moves quickly. Just before emerging from 

 its crystal envelope, the rapidity of its motion is very great ; 

 and a wondrous spectacle it is to behold many hundreds 

 of them whirhng and whirling about till they escape into 

 the water, where they swim to and fro Kke crowds of tiny 

 Nautili disporting themselves on the ocean. 



* In the ova of an Adceon, which spawned in my vase, I observed the same 

 want of symmetry : the yolk-mass divided in each case into two unequal 

 halves. 



■f I hesitated to record in the text what I found in my Tenby note-book ; 

 namely, that these embryos sometimes amount to as many as six in one chorion, 

 because as the observation was made when I was comparatively new to the sub- 

 ject, and differed from what is said by others, I thought it possible some error 

 of interpretation might have occurred. I have since satisfied myself that my 

 original note was accurate, and I have at this moment a coil of Aplysia eggs 

 in process of development, in some of which there arc six, seven, and even eight 

 embryos actively rotating in each chorion. 



