Plate 58. 

 1-4. Plexechinus cinctus A. Ag. ; Station 3424. 



1. Specimen 20 mm. in length, seen from the actinal side. 



2. The same, seen from the abactinal side. 



.'3. The same, seen in profile facing the left posterior interambulacral area. 



4. The same, end view, facing the anal system and odd posterior ambulacrum. 



5. Urechinus Naresianiis A. Ag. 



6. Actinal view of specimen, 30 mm. in length ; '' Blake " Exp., 1878-79, Station 222, < 

 St. Lucia. 



