IKi POTERIOCRINID.E PENTACRINUS. 



vertebras. This specimen I endeavoured to preserve, but it was totally destroyed by 

 the ants, who eat every cartilage, so that it fell to pieces." 



From the plated integument which extends along the inner sides of the rays and 

 tentacula, some idea may be formed of the immense number of calcareous plates which 

 constitute the indurated skeleton of this animal. According to a calculation made by 

 the late Mr. Miller, and there is no reason to doubt the correctness of this calculation, 

 it requires about two hundred plates to cover the membrane which protects the channel 

 inside each tentaculum, so that many thousand pieces are required for this purpose alone. 



The whole external surface of the specimens brought to Europe are devoid of the 

 membraneous covering which is reported to envelope the living animal, and they appear 

 in their preserved state of a delicate straw colour, and so highly polished as to resemble 

 fine enamel. 



The muscular or fleshy substance intervening between the joints of the column, the 

 claspers, and the rays must be of inconsiderable thickness, but of wonderful tenacity 

 or it could not hold the joints so firmly together as to admit of the column being 

 fractured obliquely through several consecutive joints, instead of its yielding in the 

 natural divisions when the force which tore it from the ocean bed was applied to it. 



It should be observed that throughout the indurated frame work of these curiously 

 constructed creatures we constantly find the membraneous matter closely intermingled 

 with the calcareous secretions which give stability to the whole structure. 



One of the specimens in the Bristol Institution may be considered as a variety of this 

 species. The column is not so deeply sinuated between the prominent angles as in the 

 specimen described, and there is some indication of the rays being more numerous. If 

 this latter point should be hereafter clearly established it will entitle it to specific 

 distinction. 



Of all the abounding forms of the Lily-stars that once spread their waving rays in 

 the ancient seas, the P. Caput Maduccc is the chief existing representative, and therefore 

 on that account the more interesting to the naturalist, who can trace back the genus, 

 species by species, to its first appearance in the seas where the lias formed the bed of 

 an ocean which flowed os^er a great part of the then submerged Europe; and when, 

 judging from analogy, the temperature of the sea in the latitude of England was 

 similar to that of the waters which now flow around the shores of Barbadoes. 



