ECHINODERMATA OP NEW ENGLAND. 



71 



1. The adult pluteus of Ophiopholis has two arms very 

 much longer than the others. 



2. The pluteus of Arbacia has eight oral and two anal 

 arms. No other New England pluteus has the two anal 

 arms as far as known. 



3. The pluteus of Strongylocentrotus has eight oral 

 arms and epaulettes, ciliated appendages formed by the 

 outgrowth of the ciliated chords at the angle of the junc- 

 tion of the arms (larger) with the body. 



PLUTEUS OF OPHIOPHOLIS. 



4. The pluteus of Echinarachnius is without epaulettes, 

 with eight arms, six of which bear marked pigment spots 

 near their extremities. 



C. False pupa. 



The false pupa is probably a young of Lophothuria. It 

 is globular, bright red in color, opaque, with a cluster of 

 knobs at one pole and two knobs on one side. The former 

 develop into the tentacles of the adult, the latter into feet 

 of the soft foot-like region of the body. 



