CHAPTER XL VIII. 



ENCRINITES AND ZOOPHYTES OF THE SILURIAN SYSTEM. 



Crinoidea, PL 17 and 18. Polyparia, PL 15., \blis., 16. and 16 bis. Other 

 Zoophytes and Nondescripts, PL 26.— Annelida of the Upper Cambrian 

 Rocks, PL 27. 



THE examination of the Crinoidea and Zoophytes affords the same result as the previous 

 inquiry into the characters of the higher grades of animals, and equally demonstrates 

 the distinctness of the zoological types of the Silurian System. 



In this chapter I have been assisted by Professor Phillips, Mr. Konig, M. Milne 

 Edwards, Mr. W. S. MacLeay, and Dr. Beck ; but the chief labour has devolved on Mr. 

 Lonsdale, whose description of the corals is the condensed result of a long and critical 

 analysis 1 . 



Crinoidea. — The continued application of a good naturalist is required to prepare 

 a monograph of these curious tenants of the deep. Although they occur in nearly 

 all the sedimentary deposits, ranging from the youngest to the oldest, one English 

 work only, that of Miller, is exclusively devoted to their consideration. Availing him- 

 self of all the specimens which were accessible at the period when he wrote (1821), 

 Miller established several new genera and species, and classed them according to their 

 anatomical structure. As, however, the older rocks of which I treat were then little 

 known, his list of their crinoidal contents is necessarily meagre, three species only of 

 that age being described by him. 



The subject has been since much extended in England, by the labours of Mr. Gil- 

 bertson and the writings of Professor Phillips, who gives a perspicuous account, and 

 excellent figures of forty species of Crinoidea of the Carboniferous Limestone, seven of 

 which only are figured in Miller's work. 



My object being restricted to the illustration of the older rocks, I need not here ad- 

 vert to those works of foreigners and our countrymen, in which the species of Crinoidea 

 peculiar to the younger formations are described, though I may be permitted to refer 



1 To illustrate the Silurian Rocks I presented a series of their fossils to the Geological Society, and my friend 

 Mr. Lonsdale undertook the arduous task of comparing all the corals with their congeners in the Carboniferous 

 Limestone of our own country, and with those of the transition rocks of the continent. I cannot too gratefully 

 acknowledge my obligations to him for his unwearied exertions and their important results. (See p. 675 et seq.) 



