414 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [^7 14, 



spinules of the first-mentioned structures often give them a pinnate 

 appearance. Granulation and radiating lines mark the upper part 

 of the capitulum ; and these last are especially well seen when the 

 crateriform projection resembling an oral orifice is visible. 



The only perforations of the calcareous investment are at the 

 distal end of each tentacular process, and on the upper surface of 

 the capitulum. The general surface is not perforate. There are, 

 however, in a few specimens some few irregular-shaped openings on 

 the underside of one or two tentacular processes ; and a few stems 

 present indications of an opening close to the capitulum. It is 

 evident after careful examination that the openings in the distal 

 end of the tentacular processes are normal ; and they may have 

 permitted the internal structures to communicate with the outside 

 medium ; but the inferior openings are either the result of com- 

 pression, or of the dislocation of ornamentation. The capitular 

 opening, with its radiating lines and projecting eminence surrounded 

 by the tentacular processes, is a part of the structural ceconomy of 

 the form ; and even when the upper capitular surface is flat it may 

 be discovered by gentle scraping. It would appear that several 

 flap-like processes enter into the composition of the prominence 

 which ends in the opening, after the fashion of a metastome. The 

 openings in the stems are to be referred to the fracture of a 

 calcareous and hollow process — which is to be seen intact in a few 

 specimens, and broken across at a short distance in others. 



The tentacular processes vary in length and in number. The 

 extreme length may be half an inch ; and the position of many of 

 them indicates that they were not absolutely rigid. Some are long 

 and others are short in the same whorl ; and one specimen may have 

 seven, whilst others may present four, five, eight, or more tentacles. 

 Usually one process is larger than the others, and not symmetrically 

 placed. 



There are no cellular dissepiments within the cavities of the 

 capitulum and stem ; and the calcareous investment of these struc- 

 tures is thin, readily scraped, and in no way resembles the calcite of 

 the Echinodermata. 



In the communication to the Royal Society, my colleague and I 

 represented the form, which clearly could not belong to the Echino- 

 dermata, Zoantharia, or Polyzoa, to be one of the Hydroida, having 

 affinities with the recent Bimeria vestita (S. Wright). 



In this genus there is a chitinous coat, by which sand grains 

 and spicules are mechanically suspended, covering the base, stem, 

 and body and tentacles, leaving an opening for the metastome and 

 for the distal end of the tentacles. 



"We considered the fossils to be the trophosomes of a hydroid, and 

 that the process beneath the capitulum on the stem might be the 

 gonosome. 



The crateriform aperture we believed to be the mouth : and we 

 assumed that the opening at the distal end of the tentacular 

 processes gave exit to a ciliated tentacle during life. 



Parasitic (or, rather, placed) upon a Fenestdla, the form would 



