12 



tached and acquired the full characters of a bare- eyed 

 Medusa* 



This remarkable phaenomenon is best shown in the cla- 

 viform Corallines, and has been especially described by 

 Lovenf in an excellent memoir on the Syncoryne ramosa, 

 and by Steenstrup in the Coryne Fritillaria%. This spe- 

 cies originally developes a many-armed digestive polype or 

 individual, which retains a large proportion of unchanged 

 germ-cells : these, by the stimulus of the excess of nutri- 

 ment, begin to repeat the process, and push out buds in an 

 analogous position to that in the Hydra fusca, viz. around 

 the base of the stomach of the first or parent animal : but 

 the buds, instead of repeating the form and condition of 

 that animal, take on a higher form, resembling that of a 

 bell-shaped Medusa ; they become detached and swim off 

 to a distance, forming and discharging the ova, which, as 

 Steenstrup conjectures, in their turn develope the fixed 

 polype-shaped Coryne. 



This stage of the cycle has not yet been the subject of 

 observation ; but, by the analogy of the larger Medusae, is 

 the more probable process than that direct metamorphosis 

 of the medusiform individual into the pedunculate poly- 

 poid individual, which V. Beneden has described by the 

 aid of a conjectural figure in the Tubularia . 



The medusiform ovigerous locomotive or distributive 

 individual of the Coryne and Campanularia dichotoma is 

 obviously homologous with the polypiform ovigerous in- 

 dividual, which seems to nurse, as it were, the ova into 

 6 planulae y in the Campanularia geniculata ; and the nutri- 

 tive gemmiparous polypiform individuals in all the com- 



* See the beautiful and philosophically treated monograph on the 

 Gymnophthalmata, by Prof. Edw. Forbes ; published by the Ray Society. 

 4to, 1848. 



f Wiegmann's Archiv fur Naturgeschichte, 1837, p. 322, t. vi. 



I ' On the Alternation of Generations/ translation by Raj Society, 

 8yo, 1845, p. 26, pi. 1. figs. 41-45. 



Recherches sur I'embryogenie des Tubulaires, 4to, 1844, pi. 2. fig. 5. 



