492 Observations on the 



shows no indication of which ray has been removed, and 

 each preserving their well-known specific characters. 



4. A specimen of the type of Actinocrinus umbrosus, 

 Hall, has two deep incisions, one on each side, directed 

 towards the centre, entirely dividing the brachial disk, 

 reaching downward about half the height of the body, and 

 their upper ends approaching each other at the centre of 

 the dome, with only a distance about equal to the diam- 

 eter of the proboscis intervening. These incisions, instead 

 of healing in such a manner as to restore the natural sur- 

 faces, seem to have widened by sloughing, and finally 

 healed, having the injured surfaces completely incrusted 

 with an integument of small plates. The other parts of 

 the body are all well developed, and the animal seems to 

 have lived in perfect health after its wounds were fully 

 healed. 



5. Several instances have been observed where parts of 

 several adjacent arms in Platycrinus, Actinocrinus, and 

 Poteriocrinus have been broken off nearly as far down as 

 the primary radials ; the animals dying before their entire 

 replacement, we see miniature duplicates of the lost parts 

 sprouting from the broken ends, perfect in every part, and 

 evidently wanting only time to become as good, and per- 

 haps as large, as the lost ones were. 



6. A specimen of Rhodocrinus is found to have lost all 

 the arms of two rays, which were removed at their point 

 of junction with the body, and the parts have been healed 

 in such a manner as indistinctly to show the place where 

 they were formerly attached. 



7. Instances are very common of the loss of more or 

 less of the simple arms of Actinocrinus, and the healing 

 up of the apertures thus left ; the parts often being closed 

 so neatly as to leave no indication of the loss having 

 occurred, except the want of conformity of the ray or 



