PHYSIOLOGICAL CONSIDERATIONS. 
431 
presents the angular column of the Pentacrinite ; 
'''ith this one exception, pentangular columns 
first began to abound among the Crino'ideans at 
^he commencement of the Lias, and have from 
whence extended onwards into our present seas. 
'I'heir several species and even genera are also 
fitnited in their extent; e. g, the great Lily 
^-ncrinite (E. moniliformis) is peculiar to the 
^tischel Kalk, and the Pear Encrinite to the 
^^iddle region of the Oolitic formation. 
The Physiological history of the family of 
^-ncrinites is very important ; their species were 
’iriinerous among the most ancient orders of cre- 
eled beings, and in this early state their con- 
struction exhibits at least an equal if not a higher 
fi^gree of perfection than is retained in the exist- 
'’^g Pentacrinites; and although the place, which, 
^s Zoophytes, they occupied in the animal king- 
fioin, was low, yet they were constructed with a 
perfect adaptation to that low estate, and in this 
Primeval perfection they afford another example 
variance with the doctrine of the progression 
^f animal life from simple rudiments through a 
Series of gradually improving and more perfect 
fibrins, to its fullest development in existing spe- 
cies. Thus, a comparison of one of the early 
fibrins of the Genus Pentacrinite, viz. the Eri- 
trean Pentacrinite of the Lias, (PI. 51 and PL 
'^2, Pig. 2, and PI. 53) with the fossil species of 
*^ore recent formations, and with the existing 
