694 MESSRS. P. MARTIN DUNCAN AND H. M. JENKINS ON PALiEOCORYNE. 
The height of the form is not more than ^ inch, and the length of the longest ten- 
tacular process is about ^ inch. The fossils are composed of carbonate of lime. 
The symmetry and elegance of the little fossil are heightened by its minute but ela- 
borate ornamentation. The proportions of the body, stem, and base are those of the 
most symmetrical architectural pillars ; and the elegant outlines of the tentacular pro- 
cesses are rendered more striking and less monotonous by the presence of spicules and 
of long fluted lines of delicate depressions, whose little spines are occasionally preserved. 
The upper surface of the body is granular, and the stem is ornamented with longitudinal 
flutings and minute processes. 
The general appearance of the fossil is that of a long straight-armed starfish reversed 
and fixed on a stiff stem with an expanded base. 
There was more than one species of this organism in the blocks of shale examined*, 
and many specimens had their tentacular processes in different stages of development. 
It is evident that the organism had attached itself to Fenestellae, but that it did not 
derive its nourishment from that Polyzoon. The delicate polypary of the Fenestelloe 
being slightly flexible and containing great numbers of ciliated Polyzoa, they afforded 
an excellent foundation and support to the stiff-stalked and rigid-limbed little radiate 
animal that forms the subject of this communication. 
The associated Brachiopoda, Madreporaria, Crinoidea, Polyzoa, and the small pedun- 
culated radiata were dwellers in rather deep water. Their modern representatives live 
at considerable depths; and the stoneless condition of the shales in which the fossils are 
found, and the perfect condition of the organic remains, indicate their deposition on a 
sea-bottom where there was no rapid current, but, on the contrary, a comparatively quiet 
state of things. 
II. Minute anatomy . — The base, stem, body, and tentacular processes are hollow, and 
their cavity is continuous throughout the cells of the attachment, the ascending stem, 
the expanding body, and the radiating processes; and it has one upper and central 
communication with the outside. The cavity occupies a large proportion of the animal, 
and the enclosing hard structure is but a thin shell. 
The body is not, however, a simple hollow cavity surrounded by a thin layer of hard 
structure through which the canal-like cavities of the tentacular processes enter ; for 
these processes continue to be separate for some distance within the body, and their 
canals only unite very centrally with the cavity of the body. 
The cavity of the body, thus enlarged, opens below into that of the stem, and above 
by means of a very small foramen, the oral orifice. 
This orifice is closed when the upper surface of the body is flat, and then only a con- 
tinuous granular layer of hard tissue is to be seen. Slight scraping with a knife soon 
exposes the orifice. 
When the upper surface of the body is swollen and projecting, the central opening is 
* The specimens were discovered and collected by James Thomson, Esq., F.G.S., of Glasgow, and by him 
forwarded to us for description, and for the determination of the zoological position and affinities of the fossils. 
