RKPORT ON ZOOLOGY. ^4-1 



It is probably to this last group of zoophytes, containing the 

 more perfectly organized genera, that the animal belongs which 

 Mr. Thompson has described mider the name of Polyzoa in the 

 fourth number of his Zoological Researches. This name he 

 has applied as a general title for the animal inhabitants of seve- 

 ral zoophytes, which in their organization he considers as be- 

 longing to the Acephalous Mollusca, being possessed of a di- 

 stinct guUet, stomach, intestine, and ovarium. Such a structure 

 he has noticed in Sertularia imhricata, S. Cuscuta, S. spinosa, 

 and S. pitstulosa, and he thinks that it will probably be found 

 in all the other species of Sertularia "not furnished with ovi- 

 ferous receptacles, distinct in size, shape, and situation from the 

 cells occupied by the animals, and consequently in all the Sein- 

 alaria of Lamarck." Mr. Thompson has also observed the 

 same organization in the Flustrce, thus confirming the observa- 

 tions of Audouin and Edwards, with which, however, he does 

 not appear to be acquainted*. 



The memoirs which have been noticed above relate for the 

 most part to particular groups in the class under consideration. 

 The only work that has appeared of late years treating of this 

 entire department of zoology (I except Blainville's, which is of a 

 more general nature,) is one published by Rapp in 1829t' This 

 work is divided into two parts. The first treats of the classifi- 

 cation of the Polypi in general, presenting an arrangement in 

 which due consideration is had to the form of the animal. The 



• 1 may take this opportunity of stating, that at the same meeting of the 

 British Association at which this Report was read, Mr. Graham Dalyell brought 

 forward a memoir containing some highly interesting observations connected 

 with the mode of propagation and development of the SertularicB, as well as of 

 some other zoophytes found on the coast of Scotland. An abstract of this 

 memoir will be found in the Edinb. New Philos. Journ. for October last, 

 p. 411. 



I may also observe, that since then an important memoir " On the Stioieture 

 and Functions of tubular and cellular Po/?/pj" has been published by Mr. Jack- 

 son Lister in the second part oi the Philosophical Transactions for 1834. The 

 principal feature in this memoir is the discovery of the existence of currents 

 within the stems of the Tubularia indivisa and of all the species of Sertularia 

 which were examined by the author. The circulating fluid, which appears to 

 be in some respects analogous to that observed in Ckarce, Mr. Lister is disposed 

 to regard as an important agent in the absorption and growth of the parts. 



t Ueher die Polypen im allgemeinen, und die Actinien ins hesondere. Wei- 

 mar, 1829, 4to. I should state that a work appeared in 1819 by Schweigger, 

 entitled Anatomisch-physiologische Beobachtungen ilber Corallen, which is said 

 to contain a great many valuable observations on the structure and ceconomy of 

 zoophytes : 1 have not, however, seen it myself. Some of his researches went 

 far to prove that the CorallincB are only calcified plants. See an analysis of 

 his experiments on this subject by Dr. Grant in the Edinb. New Phil. Journ. ^ 

 vol. i. p. 220. 



1834. R 



