252 Prof. E. Hackel on the Position of the 



a group which is now maintained only by Agassiz among 

 zoologists of repute. In 1847 Frey and Leuckart separated 

 the Polypes and Acalephas of Cuvier from the Echinoder- 

 mata, and united them under the name of Coelenterata*. 

 Almost at the same time Huxley also recognized the necessity 

 for this separation, and proposed the denomination Nemato- 

 jphora for the united Acalephas and Polypes, on account of their 

 urticating organs \. At hrst Leuckart grasped the notion of 

 the Coelenterata in a narrower sense (for the three classes 

 Ctenophora, Acalephse, and Polypi). Subsequently (1854) 

 he appended the Sponges also as most nearly allied to these 

 three classes \. Instead of the denomination Coelenterata^ 

 which is now very generally diffused in Germany, I employ 

 the older denomination Zoophyta^ which is still the one more 

 generally used in England and France, for the following three 

 reasons : — 



1. The denomination Zoophyta^ which was introduced into 

 systematic zoology by Wotton as early as 1552, is nearly three 

 hundred years older than the name Coelenterata. It is true 

 that the division Zoophyta in Wotton's sense and that of his 

 successors includes not only the Coelenterata (Sponges and 

 Acalephas), but also many other invertebrate animals. But 

 exactly the same objection might also be raised, and with mucii 

 more reason, against the denomination Vermes. The primary 

 division of the animal kingdom which we now generally name 

 the phylum of the Vermes, includes only a very small part of 

 the mass of invertebrate animals which Linnasus and his 

 school embraced in the class Vermes ; in the ' Systema Na- 

 turae ' all the Invertebrata, except the Arthropoda, are called 

 Vermes. 



2. The denomination Coelenterata of Frey and Leuckart 

 has at present become indefinite and ambiguous, because by it 

 most zoologists understand only the nettle-animals (Hydro- 

 medusas, Ctenophora, and Corals), whilst Leuckart himself 

 also referred the Sponges to it. This ambiguity is got rid of 

 by our giving the name of Zoophyta to the Coelenterata in the 

 broader sense (including the Sponges), whilst we name the 

 Coelenterata in the narrower sense (after the separation of the 

 Sponges) Acalephas. Even Aristotle included under the idea 

 of the Acalephas or Cnidie (a/caX.r}<^at, KvlBai) the two primary 

 types of this group, the adherent Actiniae and the free-swim- 

 ming Medusffi. The zoology of a later period was wrong in 

 understanding only the Medusfe under the name of Acalephaa. 



* Beitriige zur Kenntniss wirbelloser Thiere, 1847, pp. 38, 137. 



t Report Brit. A.ssoc. for 185J, note p. 80. 



X Arch, fiir Naturg., Jahrg. xx. 1854, Bd. ii. p. 472. 



