180 ANTHOZOA ASTEROIDA. 



developed in a spiral arrangement, and he thinks the same law will 

 be found to regulate the position of the polypes of the Alcyonium ; 

 but in Sarcodictyon they are produced in a linear series, and they are, 

 at all events, evidently more individualized ; hence the propriety of 

 raising it to the rank of a genus, notwithstanding the similarity of 

 structure between it and the Alcyonium and Sympodium. 



I cannot distinguish dried specimens from those sent me for 

 Zoanthus Couchii, and hence I may have named some of the 

 Sarcodictyon erroneously, sent me by various correspondents. This 

 is the case, I suspect, with those from my friend Mr. W. Thomp- 

 son, and published under the name of Zoanthus in his report on the 

 invertebrate Fauna of Ireland. Rep. of Brit. Assoc. 1843, p. 284. 

 See also Ann. N. Hist. xiii. 440 : Forbes in Ibid. xiv. 415. 



The CYDONIUM MULLERI of Fleming is a member of the class of 

 Sponges. See my History of British Sponges and Lithophytes, 

 p. 195. 



The fossil Asteroida are few, and comparatively uninteresting. Remains of Pen- 

 natulae have been found in the Lower Chalks ; and Mr. Morris mentions nine species 

 of Gorgonia, none of which are identical with recent species. They appear in the 

 Silurian system, and are found in the Magnesian and Carboniferous Limestone, and in 

 the Lower Chalks. The Ventriculites of the chalks are considered by Dr. Mantell to 

 have been analogous to the Alcyonia (Medals of Creation, i. p. 275), but in Mr. 

 Morns' Catalogue they are enumerated amongst the Sponges. 



