4 
cated organization. They, according to that author, have a gelatinous con- 
tractile body, a distinct mouth, surrounded by tentacula, or branching arins, 
and a simple alimentary canal or stomach, showing no vents; they increase 
by separation or internal spontaneous productions, and show no generative 
organs. The greater part of the species adhere one to another, and may be 
considered as animals depending on mutual support. Some of them approach 
closely to the infusoria (PoLyPI cILIATI) whilst others. more distinctly 
formed (POLYPI DENUDATI) are capable of attaching themselves by means of 
a pedicle, and in many instances able to detach and affix themselves to new 
spots. 
The Potyri vaGinaT1 are gelatinous like the former, but possess an epi- 
dermis, capable of secreting horny or calcarious matter, which furnishes them 
with a point of attachment, (SerTuraRiA) ; with a sort of skeleton for the sup- 
port of their aggregate and clustered groups, (Gorcon1A); or which forms cells 
in which the animal may partially conceal itself or retreat. The Polypi of this 
order, some of which are very minute, form those elegant corneous plantlike 
skeletons and calcarious Potyparia (as these eases investing the Polypi are 
termed by Lamarck) which so frequently occur in the cabinets of scientific col- 
lectors, and from whose different configurations, characters have been derived 
which have enabled Naturalists to arrange them into differeat genera, as MApRE- 
pores, Mitiepores, Tusipores, &c. The fabrics of animals of this order, 
occasion those coral reefs, so frequent in the seas of the southern hemisphere, 
which, being first elevated by the spoils of successive generations to the surface 
of the water ; then covered with sand derived from their own detritus, and that 
of sea shells ; and lastly, affording a lodgment to seeds casually wafted; in time 
assume the character of verdant islands. Thus strangely do the minutest 
and seemingly least important inhabitants of the ocean become the parents of 
new tracts of land. Their remains in earlier ages have contributed, in many 
instances, to form those masses which constitute the rocky strata of our 
present continents, and they are to be found in great variety and abundance 
in the very first formations that exhibit any remains of the animal kingdom. 
Passing by Lamarck’s Poryr1 tu BIFERI, we come to his PoLyPI NATANTES. 
It is in this order, which appears to me ill defined, that he places together 
with the genera Pennatuta, Vircutaria and Umperiuaria, the genus 
Encrinus, describing two species, the ENcRINITESs MONILIFORMIS and the 
Penrtacrinus Caput Mepus& of the present Monograph, The character of 
