88 CLASSIFICATION OF MEDUSAE. 



phytons comprising the first bud or plumule. A series of similar buds may be produced 

 until one of different aspect is developed, composed of a generation of altogether different 

 individuals, through whose agency the foundation of a new series of generations is laid in the 

 formation of the ovum or seed. Whether we style the members of one generation nurses, or 

 call them all by the same name, does not matter so far as the fact and law of an alternation 

 of generations is concerned. 



I see no reason therefore to dissent from the theory of Steenstrup ; it is the simplest and 

 most intelligible, as well as most original expression hitherto offered of the astonishing facts 

 which he was the first to generalize. Granting it, we can no longer adopt the usually 

 accepted classification of Radiate animals, nor separate them into Echinodermata, Acalepha, 

 Zoophyta, and Sponges, as so many distinct and equal orders ; but must unite the Acalephee 

 with the Zoophyta, excluding from the latter the Bryo%oa which are polypoid Tunicata. 

 The Acalephce or Arachnodermata must undergo reconstruction, for the Polypes cannot even 

 be regarded as forming a primary division when united with the usual members of this great 

 section. They evidently form part of a sub-class with the Biscophorce, equal to the sub- 

 classes, Ciliograda, Cirrhigrada, and Physograda. The Biscophyrce must again undergo 

 subdivision into orders. The Antho%oa will stand first, next the Steganopthalmata, then the 

 Gymnopthalmata, and lastly the Hydroida. That the Antho%oa are intimately related to the 

 Medusae is evident to any unprejudiced naturalist who has studied the structure of Lucernaria, 

 or of the Actineadcs, especially of any floating form of the last tribe, such as the Arachnactis 

 of Sars. The close affinity of these tribes has been excellently treated of in an Essay by 

 Drs. Frey and Leuckart, who, after comparing organ with organ in the Anthonoa, the several 

 usually received orders of Acalephce and the Polypes, observe, in conclusion, that these various 

 tribes ought no longer to be placed apart in a natural system. "They rather go towards 

 constituting a larger section, having one common type of structure — a type chiefly charac- 

 terised by the peculiar arrangements of the viscera and the stomachal cavity." They 

 propose to designate such division by the name of Colenterata.* 



Even among the animals figured and described in this Monograph, we see abundant 

 evidences of the close affinity of the Medusae, on the one hand, with hydroid polypes ; on the 

 other, with the Anthozoa. The 8teenstrupice are in all probability Medusa-generations of some 

 corynoid polype, yet, through Euphysa, they are intimately related with Sarsia, and through 

 Sarsia with Slabberia, whence the affinities upwards are easily traced. The Turris digitalis, 

 on the other hand, closely reminds us of an Actinea ; so nearly, that when I first found a 

 specimen, I mistook it for an animal of that genus. 



Thus, in the end, we revert, curiously enough, to the views of the affinities of these 

 animals -proposed by Aristotle, who plainly included, under the designation of aKaXjj'^jj, both 

 ActinecB and Medusa; not from any vague guess, or in compliance with the popular recognition 

 of their resemblances, but from a careful study of their structure and habits, as the varied 

 notices of them preserved to us in the first, fourth, fifth, eighth, and ninth books of the ' History 

 of Animals,' prove beyond question. 



* Frey and Leuckart^s Beitrage, p. 38. 



