388 APPENDIX. 
splendid Venus’ girdle of the Mediterranean (Cestum), the colours 
of which are as varied as those of the rainbow. The actual body 
of the animal, which lies in the centre of the long belt, is very 
small, and constructed exactly like that of the melon-jelly 
(Cydippe), which floats above to the left (16). On the latter are 
visible the eight characteristic fringed bands, or ciliated combs, 
of the ctenophora, and also two long tentacles which extend right 
across the page, and are fringed with still finer threads. 
Prates VIII. anp TX. (Between pages 170 and 171, Vol. IT.) 
History of the Development of Star-fishes (Hehinoderma, or 
Estrella). The two plates exhibit their alternation of generation 
(vol. ii. p. 168), with an example from each of the four classes of 
Star-fishes. The sea-stars (Asterida) are represented by Uraster 
(A), the sea-lilies (Crinoida) by Comatula (B), the sea-urchins 
(Echinida) by Echinus (C), and finally, the sea-cucumbers 
(Holothurie) by Synapta (D). (Compare vol. ii. pp. 166 and 176). 
The successive stages of development are marked by the numbers 
1-6. 
Plate VIII. represents the individual development of the first 
and non-sexual generation of Star-fishes, that is, of the nurses 
(usually, but erroneously, called larve). These nurses possess 
the form-value of a simple, unsegmented worm-individual. Fig 1 
represents the egg of the four Star-fishes; and it, in all essential 
points, agrees with that of man and of other animals. (Compare 
vol. i. p. 297, Fig. 5.) As in man, the protoplasm of the egg- 
cell (the yolk) is surrounded by a thick, structureless membrane 
(zona pellucida), and contains a globular, cell-kernel (nucleus), 
as clear as glass, which again encloses a nucleolus. Out of the 
fertilised egg of the Star-fish (Fig. 41) there develops in the 
first place, by the repeated sub-division of cells, a globular mass 
of homogeneous cells (Fig. 6, vol. i. p. 299), and this changes into 
a very simple nurse, which has almost the same shape as a 
wooden shoe (Fig. A 2—D 2). The edge of the opening of the 
shoe is bordered by a fringe of cilia, the ciliary movements of 
