ACTIXOroDOUS HOLOÏHUKIOIDEA. 



13 



All the spscimeus are more or less contracted. 



Description'. — Tentacles 20, may be reduced to 19 ur to 10. 

 Color in alcohol, lighter or darker shades of b^o^vn. Some with 

 decided purple tinge, others appear l)leaclied and white. Young 

 specimen translucent without color. Tentacles Mght yellow, in 

 young specimen of a decided orange color. 



Body cylindrical or subcylindrical, without any marginal 

 border between the ventrum and the dorsum. Tapers much more 

 toward the posterior end than toward the anterior. Mouth 

 ventral, anus terminal. 



In the specimens which show the arrangement of the am- 

 bulacra! appendages best, dorsal papillae are in six longitudinal 

 rows : one on each side at the boundary between the dorsum and 

 the ventrum and belonginc: to each lateral ambulacrum, and two 

 belonging to each of the two dorsal ambulacra. Each papilla has 

 a large wart-like conical base, from the top of which a much more 

 slender papilla arises. In a specimen which shows this best, the 

 whole dorsum appears as if it wx-re covered entirely by these 

 conical warts, although in fresh specimens there must have been 

 some space between and around their bases. The slender 

 terminal papilla-like part is short in the posterior parts but 

 becomes as long as 8 mm. in the anterior region. The papillae on 

 the dorsal side of the mouth have small bases, but are especially 



