98 THE AQUARIAN NATURALIST, 



was examined every day with a single lens, and after 

 a few days, minute bodies about the size of rape-seeds 

 were detected swimming about amongst the eggs. 

 These proved to be the hatched young of Cydippe. 

 The rest of the ova were found in all stages of ad- 

 vance towards full development, as represented in 

 PL I. fig. 10, a, b, c. Fig. 10, a, shows the newly 

 extruded egg, with yolk and shell. In fig. 10, b, the 

 yolk has become irregular in shape, granular and 

 opake. In fig. 10, c, the embryo is elongated into 

 an irregular cylinder, and is encircled by a wreath 

 of long cilia, by which it is rapidly whirled round 

 in the shell. In fig. 10, d, the ciliary wreath is 

 broken up, and divided into four bundles the upper 

 part of the embryo has become transparent by the 

 gradual absorption of the yolk, and the tentacles 

 have appeared as simple granular threads, and as yet 

 destitute of the lateral cirri which adorn those of the 

 adult. In fig. 10, e (representing the newly-hatched 

 Cydippe), the four bundles of cilia have extended them- 

 selves into short bands, and the tentacles have become 

 greatly lengthened. At this point, unfortunately, 

 Dr. Strethill Wright' s observations were arrested, all 

 the young Acalephs having died at this stage, which 

 they attained in about five days ; and he was not able 

 to find other specimens either in the first or more 

 advanced stages of development. Should a similar 

 opportunity present itself to any of our aquarium- 

 cultivating readers, we sincerely hope that more for- 

 tunate circumstances will enable them to complete a 

 series of observations at once so interesting and 

 novel. 



