80 



REPORT 1851. 



Fuvtliermore, each group returns into itself; the fi'ee floating Actiniae nearly ap- 

 proximate Berbe, and Lttccrnaria is but a fixed Medusa. 



Should these considerations eventually prove to be well-founded, the author con- 

 siders that it will be necessary to break up the class Radiata of Cuvier into four 

 groups, severally capable of being defined by positive characters. ' Supposing the 

 Neniatophora to form a sort of central group, we have on the one hand the Ascidians 

 and the Bryozoa, leading to the Mollusca; on the other the Echiuoderms and Entozoa 

 (in the widest sense), leading to the Annulosa ; whilst the Polygastria, Sponges, and 

 Gregarinidte (if indeed they are not rather to be considered only as the lowest forms 

 of the other three groups) conduct us towards the lowest plants. These relations may 

 be thus represented : — 



MOLLUSCA. 



ANNULOSA. 



Ascidians./ Brjozoa. 



PROTOPHYTA. 



Description of a New Form of Sponge-like Animal. By T. H. Huxley, F.R.S. 



The author described a gelatinous substance found in almost all seas, in masses 

 varying in size from that of a pea to that of a walnut. This mass is an animal of 

 extreme simplicity, analogous to the Palmellag in the vegetable kingdom, and con* 

 sisting of a number of simple cells united by a gelatinous connecting matter, con- 

 taining siliceous spicula. 



The author pointed out the importance of this creature as connecting the Spongice 

 Gregarinidce and Polythalamata. 



On the Land and Freshwater Mollusca found within seven miles of Nottingham. 

 By E. J. Lowe. F.R.A.S. 



1st. Land Shells (Univalves) . 

 Azeca tridens, rare at Highfield House. 

 Arion ater and A. hortensis, common, 

 Achatina acicula, rare at Ratcliffe. 



