DEVELOPMENT. 15 



of propagation by gemmation was long supposed among Radiata to be an especial privilege 

 and distinction of the true zoophyte ; but the march of discovery and the revolutions of 

 science^ do away with such artificial distinctions, though the recognition of them in their time 

 gave no small impulse to the onward progress which was eventually to destroy them. The 

 discoveries of Sars, Dalyell, Loven, Wagner, Van Beneden, Dujardin, and Steenstrup have 

 changed the face of this section of creation seriously, and prophetically indicate many coming 

 changes. It is the duty of the philosophical zoologist to keep pace with the railroad speed 

 of modern research, and whilst conservative of all past statements, as yet insufficiently 

 combated, never to hesitate to cast away preconceived notions and old teachings the moment 

 they are clearly shown to be untrue. " Free and unprejudiced spirits will neither antiquate 

 truth for the oldnesse of the notion, nor slight her for looking young, or bearing the face of 

 novelty."* 



The polypes of the genus Coryne and its allies, of Tubularia and Eudendrium, and of 

 the beautiful Corymorpha, send forth at certain times bud-like bodies, more or less sym- 

 metrically arranged around their heads. These bodies have long been recognised as 

 young anhnals, though not until very recently was it known that the creatures so produced 

 bear no resemblance to their parents, but were indeed true Medusee, and not polypes, which, 

 however, in their turn produced eggs capable of producing polypes. Such appears to be the 

 true interpretation of the phenomenon — a part of the justly celebrated theory of alternation of 

 generations which has originated in the imaginative mind of Steenstrup. On the bearing of 

 such discoveries on the better classification of the Radiata, I shall have to make a few remarks 

 presently. Now, among the AcalepJm, no such reproduction by gemmation in the manner 

 of the Coryne was known until discovered in 1836 by Sars, who had previously been the 

 first to announce the surprising fact of the intermediate Strobila condition of the higher 

 Medusae, a discovery made independently and simultaneously in Scotland by Sir John Graham 

 DalyeU. 



The discovery made by Sars was that certain forms of naked-eyed Medusae multiply 

 their species by means of gemmation, the buds being produced either from the walls of the 

 peduncle or stomachal proboscis, or from the surface of the ovaries, the former mode occurring 

 in the " CytcBis octopunctata" {Lhnia octopunctata, Mihi), the latter in Thaumantias multi- 

 cirrata. In both cases, the new individuals were not different from, but similar to, their 

 parents, and, in one instance, provision seemed to be already made in the new-formed individuals 

 for continuing to propagate by the same mode other individuals similar to itself. The full 

 account of these remarkable and highly important observations, illustrated by excellent figures, 

 is contained in the lately published ' Fauna Norvegica,' a most admirable work, by one of the 

 greatest of living investigators of life in the sea. I shall extract it hereafter when describing 

 the Li%%ia, in the second part of this essay. At present 1 shall cite the summing up given by 

 Sars, and his notice of the phenomenon as it occurs in the Thaumantias. 



" We now recognise a mode of procreation and development hitherto unknown among the 

 Acalephae. From a certain part of the body (in this instance the tubular stomach, hanging 

 independently in the cavity of the disk) roundish knobs grow forth from the upper towards 

 the lower part, which gradually assume the shape of a bell, by opening themselves at the free 



* Henry More. 



