Plate 86. 

 1-5. Pilematechinus Rathbuni A. Ag. ; Station 3374. 



1. Part of ambitus and adjoining abactinal coronal plates to show the resorption of 



the primary tubercles in a specimen 95 mm. in length. 



2. Part of fifth and sixth plates from the mouth, showing primary tubercles in different 



stages of resorption, from the right anterior ambulacrum. 



3. Seventh plate from the mouth, showing partly and wholly resorbed tubercles in the 



region crowded with primary tubercles of the odd interambulacrum. of a specimeu 

 85 mm. in length. 



4. One of the plates of the odd interambulacrum, seen from the interior, showing tb€ 



splitting up of a primary plate of a specimen 85 mm. in length. 



5. Anal system of a specimen 95 mm. in diameter. 



