80 



The FIVE SCAPUUE (fig. 7.) adhere to the upper edge of the pelvis, are 

 thick, short, bevelled at the summit, with an excavation, and a horse-shoe 

 shaped impression for the insertion of the arms. 



The pelvis and scapulae (fig. 1. to 7.) are thicker near the centre than at their 

 margin of adhesion, and display their muscularity in a conspicuous manner. 

 Previous to the exertion of the contracting muscular power of the animal they 

 are nearly smooth, sloping towards the sutures (fig. 1. 22. to 24.) On contrac- 

 tion, the bevelled edges become rounded, and the smooth surface undulating 

 and corrugated, (fig. 3. and 6.) On still further contraction, the A'arious 

 branches of the muscles become visible, and the pelvis shows two or three se- 

 ries of tubercles (fig. 1 . 4. and 7.) viz. four, three, and two, in the smaller plate of 

 the pelvis, and six, four, and two, on each of the two larger. In this case five or 

 six tubercles are arranged in a crescent on the scapula, below the horse-shoe-like 

 depression, having sometimes another similar series under them. In other speci- 

 mens I have observed each tubercle in this second or lower series, assuming an 

 oblong figure, (fig. 18. and 19.) and traced it until it connected with the tubercle 

 above it, and forming, together with it, a single ridge, (fig. 17. 20. and 21.) thus 

 displaying on each of the scapulae several radiated ridges. In a specimen in my 

 possession (fig. 5.) a still greater number of tubercles are visible, which are 

 irregularly arranged. 



AKMS AND HANDS. On each of the scapula is inserted a cuneiform joint, 

 forming the arm (fig. 8. and 9.) on which the two joints of the first series of the 

 hand affix (fig. 10.) having each at their summit a cuneiform joint, sending 

 off on the one side a finger, and on the other the second series of the hand, sur- 

 mounted by another cuneiform joint supporting two fingers. 



The FINGERS (fig. 1.) are formed each of two series of joints resembling 

 those of Encrinites moniliformis, and sending offlike them series of tentacula. 



The INTEGUMENT over the abdominal cavity is protected by large and 

 thick angular plates, and is capable of elongating itself in the centre into a pro- 

 boscis, analagous to that in Actinocriuites, which will be hereafter described. 



