NATURAL HISTORY SOCIETY OF GLASGOW. 91 



III. — Notes and Observations on injured or diseased Crinoids.'^ 



Any observer who has explored the limestones and accom- 

 panying shales of the Carboniferous period, could not have 

 failed, amongst tlie myriads of fragments of Crinoids, to have 

 been attracted by the occasional occurrence of tumid or partially 

 enlarged columns. 



Ure, in stating the characteristics of Crinoids obtained by 

 him, remarks that "Some appear to have been wounded in a 

 recent state; this is indicated by an unusual swelling, which in 

 every case exhibits a large and deep puncture, probably the 

 cause of the swelling." (History of Rutherglen and East Kilbride, 

 1793, page 324). 



Miller, in his work on the Crinoidea, is more elaborate in 

 his remarks on the tumid condition of these stems. Speaking 

 of the Poteriocrinus crassus, he states: "Its column has some- 

 times numerous joints swelling gradually out, and thus giving 

 it a barrel-shaped appearance, generally pressed in on one of 

 its sides, and becoming there concave, with a central perforation 

 evidently leading to the alimentary canal. This has all the 

 appearance of a cicatrized wound; and as the alimentary canal 

 is not increased in the column, the swelling can only arise 

 from a more rapid secretion from these joints, probably to 

 strengthen it, and to compensate thus for the injury probably 

 sustained in one of its auxiliary side-arms. The cavity before 

 mentioned was probably produced by the loss or separation of 

 the stump or side-arm from the column, and the subsequent 

 cicatrizing of the wound." (Natural History of the Crinoidea, 

 1821, page 69). 



A paper "On the cause and nature of the enlargement on 

 some crinoidal columns," by Mr Rofe, F.G.S., appeared in the 

 Geological Magazine for August, 1869, accounting apparently for 

 the cause of the appearances observed by Ure, Miller, and 

 others; but it does not seem that the facts described by Mr 

 Eofe have any such bearing. Encircling coralloids had no part 

 in the one, and there is no depression or perforation on one 

 side in the other. 



In the remarks which follow, therefore, the encrinal columns 



* Head by Mr John Young, F.G.S. (communicated). 



