ECHINODERMATA OF NEW ENGLAND. 47 



many ruffles. Chymiferous tubes dendritic. Color red 

 and blue. Body very large. 



O. arctica. 



Aurelia. Umbrella disk-shaped with a single row of 

 marginal tentacles. Eight hooded otocysts. Lips in the 

 form of four fringed arms. Chymiferous tubes branched, 

 not dendritic. Color cream or white. Body large size. 



A. flavidula. 



Dactylometra. Flexible umbrella, globular, discoid, 

 with many marginal tentacles and incised edges. Lips 

 in form of four long projecting tentacle-like appendages. 

 Color pinkish ; tentacles red. Tubes of body unbranched. 

 No peripheral vessel. 



D. quinquecirra. 



B. 



Callinema. Umbrella flat, thick with apical protuber- 

 ance. Tubes radial, anastomosing in sixteen segments. 

 Circular vessel with radial extensions. Sixteen sense lap- 

 pets. Tentacles long, numerous, arising from circular 

 vessel. Lips in curtain-like frills. 



C. ornata. 



Free-swimming larvae. 



The only free-swimming larvae of Acraspeda yet de- 

 scribed from New England are called the Ephyrse. Al- 

 though other genera occur I have found only this stage 

 of the two above-mentioned genera. The ova are borne 

 in the folds of the mouth and their development into free 

 planulse can be easily traced into the sessile stages, Scy- 

 phistoma 1 and Strobila, descriptions of which do not come 

 in the province of this work. The youngest free larva 



^ucernaria, which is closely allied to Scyphistoma, has cup-shaped, very con- 

 tractile body with peduncle and is found attached to Zostera or some similar 

 foreign object. Tentacles small in clusters of tuft-like bodies. Color brown or 

 light green. 



