MUSEUM OF COMPARATIVE ZOOLOGY. 195 
EXPLANATION OF THE PLATES OF ECHINI. 
PLATES I.—II. 
Conoclypus Sigsbei A. Aa. 
PrATE I. 
Fig. 1. Profile, seen facing the anterior extremity, natural size. 
Fig. 2. Profile seen from the left side. 
Piare II. 
Fig. 1. Seen from above, natural size. 
Fig. 2. Seen from the actinal side, natural size, 
PLATE III. 
Periaster limicola A. ۰ 
Fig. 1. Seen in profile. 
Fig. 2. Seen from above. 
Fig. 3. Seen from above, denuded. 
Fig. 4. Seen from below, denuded. 
All figures natural size. 
PLATE IV. 
Dorocidaris Blakei A. Ao. 
Fig. 1. Seen in profile. 
Fig. 2. Seen from above, 
Fig. 3. Seen from below. 
All figures natural size. 
PLATE V. 
Salenia Pattersoni A. ۰ 
Fig. 1. Seen in profile. 
Fig. 2. Seen from above. 
Fig. 3. Seen from the mouth side, 
All figures natural size, 
