2 
position and arrangement of the numerous fragments in my possession, and 
to make with these (as it were) disjointed skeletons. These fragments which 
presented me often with characters, that in more perfect specimens are par- 
tially concealed, pointed out that something more than the bony portion (or 
rather internal bonelike concretions of these animals, which must in this 
respect be considered as analogous in structure to the Star-fish) had been 
preserved, and had sustained the process of petrifaction, and that traces of 
muscular covering investing them were clearly observable. I was thus led to 
an inquiry into the myology of these beings, which combined with the former 
observations, aided in obtaining a more satisfactory knowledge of their 
economy, and a more correct determination of their genera and species. I 
was much pleased, when on a subsequent examination of the Pentacrinus 
caput medusz (the only recent, and very rarely occurring species) I was con- 
firmed in the correctness of the conclusions which I had deduced from the 
inspection of the fossil fragments. The course of these researches convinced 
me that the animals described by Mr. Parkinson as Encrinites and Pen- 
taciinites, and by M. Lamarck and M. Cuvier arranged under the single 
genus, Encrinus, would readily and properly form a distinct and peculiar 
family, comprehending several genera and species. The new order thus 
constructed, requires to be separated from the Potypr naranres of M. La- 
MARCK—an order to which its members were most unhappily referred by that 
author, although they possess neither of the characters indicated by that name, 
being in truth widely different from Polypi, and instead of floating freely, being 
generally fixed to one spot. They form the natural transition to the stellerid 
family, but especially to the genera ALecrTo of Dr. Leacu, and Marsupites 
of Gipeon Manet, Esq. 
As the Zoological principles adopted in this Work coincide generally with 
those of M. Lamarck, but yet in many instances, exhibit modifications of them, 
which would appear inadmissible were his opinions implicitly embraced; it will 
materially assist us in forming a clear view of the place which is assigned to 
the present order in the scale of animated nature, and illustrate the observa- 
tions which it may be necessary hereafter to introduce; to subjoin in this 
place a brief review of that part of the system of this author, (who proceeds 
from the lower and most simple to the more complicated and perfect animals) 
which includes his lowest classes, those namely, which precede and accom- 
pany that in which he places the genera of which we are now entering 
upon the description, We must begin then by observing, that according to 
