cate<l organization. They, according to that author, have a gelatinous con- 

 tractile body, a distinct mouth, surrounded by tentacula, or branching arms, 

 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 parl of the species adhere one to another, an<l 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 DENUUATI) are capable of attaching themselves by means of 

 a pedicle, and in many instances able to detach aud affix themselves to new 

 spots. 



The POLYPI VAGINATI are gelatinous like the former, but possess an epi- 

 dermis, capable of secreting horny or calcareous matter, which furnishes them 

 with a point of attachment, (SERTULARIA) ; with a sort of skeleton for the sup- 

 port of their aggregate and clustered groups, (GORGONIA); 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 POLYPARIA (as these cases 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 different genera, as M AUK - 

 PORES, MILLEPORES, TuBiPORES, &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 POLYPI TUBIFERI, we come to his POLYPI NATANTES. 

 It is in this order, which appears to me ill defined, that he places together 

 with the genera PENNATULA, VIRGULARIA and UMBELLULARIA, the genus 

 ENCRINUS, describing two species, the ENCRINITES MONILIFOUMIS and the 

 PENTACBIMUS CAPUT MEDUSAE of the present Monograph. The character of 



