CLASSIFICATION. 



37 



in his memoir on the Palseozoic Asteriadae figured as Urasfer, some ot which arc now 

 grouped in the genus Palaa-'^ter. 



M. Goldfuss^ has figured as Aslerias ohtmus, a remarkable asteriad which was 

 obtained by Alberti from the Muschelkalk of Friedrichshall in Wiirtemberg, 



It has been long known to palaeontologists that a remarkable change is observed in 

 the generic characters of many fossil animals found in the secondary formations when 

 compared with those belonging to the same classes which are entombed in the Palaeozoic 

 series. Reptiles, fishes, mollusca, and articulata afford abundant evidence of such change' 

 and the sub-kingdom radiata supplies additional proofs of the same organic law. 



As the Oolitic Asteriada3 will be figured and described in detail in this monograph, it 

 is only necessary to state here that nearly all the species belong to the genera TJrader, 

 Asfrojjecten, Luidia, Fliimasier, and Goniasirr. The fossil species all appertain to extinct 

 forms, but the genera to which they belong are nearly all living in our present seas. 



The Cretaceous Asteriadte, which have already been beautifully figured in Dixon's 

 ' Geology of Sussex,' will form the subject of a future monograph, to succeed the Cretaceous 

 Echinidsc now in course of publication. These interesting star-fishes of the Chalk period 

 range themselves for the most part in the genera Greasier, Gonloilhevs, jhiroi/onhuii, 

 St el I aster, and Arthr aster. 



The Tertiary formations have hitherto yielded very few species of Asteriadae. Those 

 from the English tertiaries, representing Astropecten and Goniaster, have been figured by 

 Professor Edward Forbes," in his Hadiaria of the London Clay ; and the specimens from 

 the Vienna basin, likewise belonging to the geneva Astropecteti and Goniaster, have been 

 figured and described by Dr. Camil Heller in his paper " fiber neuc fossile Stelliriden."'" 



CLASSIFICATION OF THE ASTERIAD^. 



The numerous forms presented by the animals of this division early induced Llhwyd 

 and Petiver to give generic names, as Asterisei"^ and Eehinasfer, to certain of the group. 

 The first systematic monograph which appeared was published by J. H. Linck* of 

 Leipsic; this work was illustrated by forty-two well-executed plates, representing the 

 leading forms known to him. This author divided the Star-fishes {Asterias, Linn.) into 

 two sections, 1. Stellis rissis. — II. Stellts integkis, characterised by the presence or 

 absence of ambulacra on the underside of the rays. In the first section, which 



1 Goldfuss, 'Fetrefacta Germanise,' Band i, p. 208, t. 63, fig. 3. 

 - Palreontographical Society Volume for 1852. 



2 ' Akademie der Wissenschaften,' Band xxviii des Jahrgungcs 18.58, Wien. 



* * De Stellis Marinis liber singularis. Tabularuni aenearum figuras,' Lepsic, ! 7',i3. 



