ROOM II. MARSUPITES. 85 



purposes, beautiful examples of these fossils may be obtained. 

 The cavities of the columns and ossicula are often filled with 

 white calcareous spar ; while the ground of the marble is of 

 a dark reddish brown colour. In other varieties of the 

 Derbyshire entrochal limestones, the substance of the fossils is 

 white, and the ground dark grey or brown ; both kinds, when 

 worked into ornaments, are very beautiful and interesting. 1 



MARSUPITES (M. Miller i). Wall-Case G. On the upper 

 and right-hand Shelf. The chalk fossils labelled Marsupites 

 in the upper compartment of this cabinet belong to an inte- 

 resting extinct type of Stelleridse, that forms a connecting 

 link between the Starfishes and the Crinoideans. Like the 

 former, it is free, and destitute of a column of support or 

 pedicle ; while it has the receptacle composed of articulated 

 plates, and flexible arms, as in the lily-shaped animals. These 

 fossils are peculiar to the white chalk deposits, and were first 

 described by Mr. Parkinson in the "Organic Remains of 

 a Former World," under the name of " Tortoise Encrinite," 

 that excellent observer having supposed, from the sculpturing 

 of the plates of certain specimens, that they were related to 

 the Actinocrinites, and had a jointed column. The true 

 characters of the original were first pointed out in my " Fossils 

 of the South Downs ;" 2 and the name Marsupites, suggested 

 by the purse-like form of the closed specimens, was adopted. 



The receptacle of the Marsupite is of a subovate shape, 

 rounded and entire at the dorsal aspect, consisting of a large 

 central plate, and a series of polygonal plates, with five arms 

 attached to the margin. The opening of the receptacle was 

 covered by an integument supported by numerous small 

 seniilunar ossicula, in the centre or side of which the buccal 

 aperture, or mouth, was placed. The external surface of the 

 receptacle is smooth in some examples ; in others it is deeply 

 sculptured with granulated lines and furrows, disposed in 

 a radiated manner ; and in a few instances the sculpturing is 

 rugous and irregular. The Marsupites vary in size from one 

 to three inches in length. The. receptacle is very capacious 



1 " Pictorial Atlas," PI. XLIX. for figures of pulley-stones and encri- 

 nital marbles: and PI. XLVII. for representations of a great variety of 

 stems of Encrinites and Pentacrinites. 



2 " The Fossils of the South Downs/' or " Illustration of the Geology 

 of Sussex," p. 184, pi. x?i. 



