ECIIINODERMATA OF NEW ENGLAND. 



39 



nous in single row. Often obscurely "hooded eyed." Pro- 

 boscis and radial tubes generally present, often absent. 



A. Without proboscis Cunina. 



B. With proboscis; 



I. Body-walls rigid .... Trachynema. 



II. Body-walls flexible Liriope. 



Cunina. Body disk-shaped, inflexible, destitute of ra- 

 dial tubes. Tentacles rigid, arise from sides of the body 



CUNINA. 

 SECTION OF THE BELL RIM OF TRACHYNEMA. 



YOUNG TRACHYNEMA. 



not from disk margin. Velum muscular, forming the lower 

 floor of stomach-cavity. 



O. discoides. 



B. I. 



Trachynema. Umbrella mitre-shaped with rigid walls, 



with quick spasmodic movements in propulsion. Onward 



motion caused in part by vibration of velum. Tentacles 



numerous with rigid bases. Eight radial tubes, generally 



