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 was very similar to the fossil, 

 Plate XI. Fig. 4, 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 lamina? 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 ap- 

 pearance, as depicted Plate X. Fig, 13, where the ramifications are 

 magnified to about double their natural size. 



In addition to the several forms, in to 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 becom- 

 ing 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 spe- 

 cies of alcyonium is there found. 



Plate XI. Fig. 5, is a part of one of the funnel-formed fossils, de- 



