123 
in securing, by the alternate contraction and relaxation of these tubes or 
fibres, the repeated efflux and renewal of the sea-water, on which the 
support of these animals appears to have depended. 
To enable me to determine more satisfactorily respecting the struc- 
ture of these fossils, I devoted two of the fungiform variety to an in- 
ternal examination. The first of these w'as very similar to the fossil 
Plate XI. Fig. 7, but was about a quarter of its size, and had its com- 
partments, resulting from the decussations of the perpendicular and 
horizontal laminae, more regularly square. A part of the inferior sur- 
face of this fossil being removed, by rubbing down about a quarter of 
an inch, and the new surface polished, the same disposition to sepa- 
rate into ramifications similar with those which have been just men- 
tioned was rendered very evident. With the hope of obtaining a 
more distinct view of the mode in which the external laminae termi- 
nated, after ramifying in the manner already described, I placed the 
other of these specimens in diluted muriatic acid, taking it out and 
examining it, from time to time, until nearly a quarter of its substance 
was thus removed. A very unexpected appearance then presented itself ; 
the ramifications, which, even at the least depth below the surface, had 
assumed a contorted form, were here, at a greater depth, displayed in 
the most elegant ramifications, bearing somewhat of a plumose appear- 
ance, as depicted Plate X. Fig. 13, where the ramifications are magnified 
to about double their natural size. 
In addition to the several forms into which this species has been al- 
ready seen to pass, I have one, with a reticulated surface, in the form 
of a bottle : the pedicle forming the neck ; and the body, first becoming 
globose, and then contracting to a narrower base, forming the belly and 
the stand of the bottle. This fossil, which is a hard and close lime-stone, 
was obtained from Saumurs, by Mr. Strange, and may be added to 
the number of curious forms, under which this species of alcyonium 
is there found. 
Plate XL Fig. 5, is a part of one of the funnel-formed fossils, de- 
