Anteditu'oian Zoologi) and Botmiy. 



275 



RADIA^TA. * 



Stelleridce^ or radiated animals of a peculiar conformation, 

 are divided into the four genera Comatula, Euryak (Astro- 

 phyton), ^sterias, and Ophiura. Of these we have only space 

 to notice 



Asterias, or star-fish, which contains several fossil species, 

 but of rather rare occurrence. They belong chiefly to the 

 chalk, wherein have been recognised 

 four species, one of which is shown. 

 {Jig. 67.) Thirteen fossil ^steriag 

 are described in the same work. The 

 rarity of perfect specimens of Stel- 

 leridae is ascribed to the proneness to 

 decomposition of the membranous con- 

 necting matter. ^sterise have been 

 observed in the oolites. In Vol. II. 

 jbterias, approaching to Penta- p. 73. supra, we have fiffurcd an un- 



gonaster, Or^. iZ<?w., vol. iii. pi. i. ii n o i ii 



fig. 1. It is the Jst. reguikris of usually pcriect onc irom the cornbrasn. 

 The figure given by Messrs. Young 

 and Bird, pi. v. fig. 5., from the alum shale, seems to be an 

 ^steria. The fossil remains of ^steriae are said to approxi- 

 mate nearly to recent species; but this remark, probably, 

 arose from the imperfect examination the subject has received. 

 We have figured one of the recent ^steriae (Vol. II. p. 115.) 

 communicated by Mr. Thompson. Dr. Fleming describes 

 eleven British species. Recent. 



Ophiura, — Beautiful star-fish, of the genus Ophiura, have 

 been noticed, by Mr. J. Phillips, in the marlstone of Yorkshire ; 



by Messrs. Young and Bird, 

 in the alum shale (pi. v. fig. 

 5.); by Mr. Miller, in the 

 lias of Gloucestershire ; and 

 they appear, though very 

 rarely, in the chalk, (^g. 68.) 

 Crinbidea, — A consider- 

 able portion of his second 

 volume is devoted, by Mr. 

 Parkinson, to this class of 

 zoophytes, the result of which 

 is, that of the two great fa- 

 milies of coralloids, the En- 

 crinites and the Pentacrinites, of which 25 species and frag- 

 ments of numerous others abound in a mineralised state. 



Opliiura Miller/, J. Phillips's Geology of York 

 shire, pi. xiii. fig. 20. 



* " Having the organs of sense and motion disposed circularly around a 

 centre or axis," 



