72 



ming stage, but the majority had only reached the later 

 periods of segmentation, appearing as tigured by Brooks, 

 in Nos. 25, 26, 27. 



At 8.00 P. M., there were large numbers in the first 

 swimming stage at the surface of the water, the cilia were 

 well defined and active ; in many cases the polar globule 

 was still observable. The majority of the embryos ap- 

 peared as figured by Brooks, in Nos. 32, 34 and 35, while 

 a few were in more advanced stages, appearing as in 36 

 and 37. The pressure of other duties prevented my 

 continuance of the observations after 11 P. M. until 11 

 A. M. on the 8th. At that time the majority of the 

 embryos were as figured in Nos. 36, 37 and 38, the latter 

 stage predominating. The shell was remarkably well 

 defined in several, but the activity of the embryo and the 

 rudeness of the instrument used, prevented my deciding 

 with certainty as to the extent of the development of the 

 digestive tract or the presence of either the mouth or 

 anus. 



At 11 P. M., on the 8th, or two days and three hours 

 after fertilization, I foimd one embryo that so exactly 

 resembled figure 36, that it might have been the original 

 from which the figure was drawn. About this time I 

 experienced my first difficulty in finding specimens, but 

 my observation of those embryos discovered was very 

 careful and close, and I have no doubt that their devel- 

 opment so far was similar to that of our own species. 

 Subsequent to this time, the intervals between my obser- 

 vations were greater, owing to the necessity of my 

 employment upon other duty ; and my absence from the 

 vessel compelled me to put the embryos under the care 

 of others ; consequently in the intervening hours, changes 

 may have occurred which are unknown to me, and many 

 of the embryos may have advanced beyond the latest 

 stages which came under my observation, but so far as I 

 know, none advanced beyond those stages figured by 

 Brooks. 



