ECHINODERMATA. 271 



of these zoophytes exist, whilst in the early ages of the world the 

 ocean must have swarmed with them. Encrinites ahounded in the 

 seas during the transition and secondary epoch. It was one of the 

 most numerous of the animal trihes which inhabited the salt waters of 

 the ancient world. In traversing some parts of France, we tread 

 under our feet myriads of these beings, whose calcareous remains form 

 vast beds of rock. The encrinites gradually disappeared from the 

 ancient seas ; their species were diminished as the globe became older 

 or modified in its conditions, so that at the present time only a few 

 types remain in our seas such as the Comatula of the Mediterra- 

 nean ; Pentacrinus, the Medusa's-head of the Antilles ; and the Eu- 

 ropean Pentacrinus all of them very rare, and probably destined 

 soon to disappear, carrying with them the last reminiscence of the 

 zoological races of the ancient world : and here lies the real interest 

 which the Crino'idea presents to the thinking man. The encrinites 

 most common in the fossil state are Pentacrinus fasciculosus, belonging 

 to the lias; Apiocrinus rotundus, which is found in the oolite or 

 Jurassic rocks ; and Encrinus liliformis, which appertains to the 

 Triassic period. These three fixed zoophytes seem to have existed 

 in great numbers during an early age of the world namely, the 

 Silurian period. They attained their maximum of development 

 during the Devonian age, after which they begin to decrease. 

 According to M. D'Orbigny, there are thirty-nine genera found in the 

 palaeozoic rocks, two in the triassic, seven in the Jurassic, five in the 

 cretaceous, and only one in the tertiary strata. Of all these genera 

 only one, namely, Pentacrinus, is foufld in the modern epoch to repre- 

 sent the varied forms of these the first inhabitants of the seas. 



The free Crinoidse, that is, those not rooted to the soil by a stem, 

 of which the Comatula may be considered the type, only appeared at 

 a later period. They are absent in the palaeozoic and triassic rocks, 

 but appear to have attained their maximum of development in the 

 Jurassic period. 



The numerous fossilized remains of these curious creations, which 

 abound in different rocks, attracted the attention of learned men at an 

 early period. The encrinites were among the earliest objects of 

 scientific description. As early as the sixteenth century, the celebrated 

 mineralogist, George Agricola, mentions them under the names of 

 Entrochites, Trochites, and Astroites. At the same time, and since 



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