332 Proceedings of the Boyal Physical Society, 



at last ruptured, and through the opening a portion of the 

 viscera were protruded, which ultimately sloughed away ; 

 at the game time a considerable portion of the external skin 

 desquamated, the animal not appearing to suffer much from 

 the process, for the opening healed shortly afterwards. The 

 animal has been kept in a small shallow vessel of sea- water, 

 with only a little piece of sea-weed in it to keep the water in 

 good condition. During by far the greater part of the nine- 

 teen months of its confinement it remained contracted, 

 seldom moving from one spot. The only food it could pos- 

 sibly have obtained must have consisted either of micro- 

 scopic animalcules or the spores of Algae. The animal is 

 still alive ; and I am therefore not in a position to say any- 

 thing regarding its internal structure. 



The dorsal region of the body, when the creature: is con- 

 tracted, is of a deep purplish-brown tint, but the ventral 

 surface is of a paler hue. The dorsal surface, when the 

 creature is distended, approaches very much to the colour 

 of the ventral aspect when in a state of contraction. 



When contracted, it is little more than a quarter of an 

 inch in length, and about the fifth of an inch in breadth ; 

 but when distended and moving about, it becomes double 

 this length, and its breadth also is slightly increased. 



The five double rows of sucking-feet are unsymmetrical, 

 the two dorsal rows being irregular in their distribution. 

 The dorsal feet are much less numerous than the ventral, 

 which they greatly exceed in size, and from which they 

 differ very much in their undilated tips, and by their being 

 seated in some instances upon rounded eminences or tuber- 

 cles of considerable size. These feet are capable of com- 

 plete retraction into the tubercles. Though the two dorsal 

 rows of feet differ very much from the ordinary arrangement 

 of these organs in the Holothuriadse, we can nevertheless 

 trace faint indications of the double character of the rows. 



The three double rows of ventral sucking-feet are fully de- 

 veloped ; the feet are placed opposite to one another, and are 

 dilated at their tips, but are only partially retractile. The 

 animal walks upon the three well-developed rows ; and if 

 turned upon the aborted ones, it immediately recovers itself, 



