ROOM II. CRINOIDEA. 83 



examples from Sussex and Kent. The chalk-flints often have 

 remains of Goniasters attached to the surface ; in the neigh- 

 bourhood of Northfleet, specimens of this kind of great beauty 

 have been collected. 1 



CRINOEDEA. Encrinites and Pentacrinites. Wall-Case G. 

 The Crinoidese have a fixed pedicle or process of attach- 

 ment, an articulated stem composed of numerous separate 

 pieces of a solid calcareous substance, and a receptacle formed 

 of a series of plates, to the upper margin of which are attached 

 arms or tentacula. They consist of two groups ; one with 

 smooth, subcylindrical stems the Encrinites; the other in 

 which the stems are pentangular Pentacrinites. 



The fossil remains of the Crinoidese have received the name 

 of Stone-lilies, from the resemblance of the receptacle of some 

 species when the animal is in a state of repose to a closed lily 

 or tulip. Only one living species is known, namely, the Pen- 

 tacrinus Caput-Medusw, an inhabitant of the Caribbean Sea, 

 of which there is a specimen at the bottom of this Case. This 

 animal has a long jointed stem, which is fixed at its base by 

 a pedicle or root-like processes, and supports a vase or recep- 

 tacle, formed of a series of calcareous plates closely adjusted 

 to each other, in which the viscera are contained. The upper 

 part of the receptacle is covered by a plated integument, in 

 which there is an opening for the mouth. From the brim or 

 margin, proceed ten multiradiate arms, which subdivide into 

 branches of extreme tenuity ; the upper and inner side of the 

 arms support numerous articulated cirri, or feelers. The 

 ossicula composing the column of support are pentangular, 

 very numerous, and articulated by striated pentapetelous 

 surfaces, and have a central perforation ; and there are arti- 

 culated side-arms, or tentacula, that radiate from the column 

 in groups of five, at different points. In a living state the 

 skeleton is covered by the integuments which secrete it ; the 

 mouth is situated in the centre of the plated integument of 

 the receptacle, and surrounded by the arms, which, when 

 spread out, with their numerous cirri, form a net for the 

 capture of the prey, and are the organs by which it is conveyed 

 to the mouth. 



The fossil remains consist of the ossicula, or bones of the 



1 " Pictorial Atlas," PL LIIL figs. 1 and 3. 



