PLATE V. 



a, anal opening. pi, plates iu continuation of disk, interradial plates 



ac, canal of arm. extending along the base of the pinnules. 



a/>, imperforate plates of anal iuterradium. pn', first pinnule. 



br, first fork of arm. pn", second pinnule. 



g, food groove. r, first radial. 



g', ambulacral groove of pinnule. sp, side plates. 



cp, covering plates. st, subtentacular canal. 



0. oral plates. ', ambulacral tentacles. 

 p, perforated plates of interradium of disk. z, syzygy. 



1. Right anterior interradial, showing the intimate connection of the interradial plates to the radials, 



and to the lower joints of the first pinnules, *. Specimen No. 8. 



2. Anal interradium of same specimen, |. 



3. Upper end of anal tube of specimen No. 7, seen obliquely from above. 



4. Showing extension of imperforate interradial and perforated perisomatic plates to the main food 



groove, and along the side of the arm, .as far as the first axillary, *. 

 5 Showing the further continuation of the interradial skeleton along the sides of the arm below the 

 side plates (s/)), beyond the first fork of the arm, *. 



6. Showing side plates protecting the food furrow in middle of first arm. These side plates are not a 



part of the extension of perforated perisomatic plates. 



7. Showing the extension of the plates of the disk along the base of one of the pinnules placed below 



the first fork of the arm. 



8. Same pinnule seen facing the ambulacral food groove. 



9. Tentacles of ambulaci-al furrow. 



