376 THE VOYAGE OF H.M.S. CHALLENGER. 



rays, which break up at their extremities into a brush-like tuft of terminals, and also 

 small discohexasters, in which numerous terminals arise from the disc-shaped expansion 

 of the principal rays. The dermal and gastral skeletons contain rough tetracts and 

 pentacts. Japan. 



Genus 5. Bathydorus, n. gen. 



Sack- or wine-skin-like forms with loose walls, and thin (always V) oscular margin pro- 

 vided with a cuff-like marginal fringe of spicules. The parenchyma contains, besides large 

 hexacts and diacts, also oxyhexasters, and in some species discohexasters. In the dermal 

 skeleton, besides the smooth hypodermal oxypentacts, numerous rough autodermal oxyte- 

 tracts occur, and in some also autodermal diacts and even monacts. The gastral skeleton 

 contains exclusively rough oxyhexacts. 



Species 1. Bathydorus Jimhriahis, u. sp. 



A large smooth wine-skin-like form, in which the thin superior oscular margin is 

 equipped with a wreath of oxydiact marginalia. The parenchyma contains, besides 

 the principal diacts, oxyhexasters with long frequently S-shaped terminal rays. The 

 autodermalia are rough cruciate oxytetracts ; the gastralia are rough or spinose ()xy- 

 hexacts. North Pacific, 2300 to 2900 fathoms. 



Species 2. Bathydorus stellatus, n. sp. 



From the external surface of the sack-shaped body, isolated oxydiacts project radially 

 or obliquely outwards. The parenchyma contains numerous stars. The dermal and 

 gastral skeletons resemble those of Bathydorus Jimbriatus. Messier Channel, Patagonia, 

 140 fathoms. 



Species 3. Bathydorus spinosus, n. sp. 



Externally like Bathydorus stellatus. The oscular margin bears a wreath of spicules. 

 The parenchyma contains oxyhexasters with long, somewhat wavy terminal rays. The 

 autodermalia are rough oxytetracts, the gastralia oxyhexacts of varying size, sometimes 

 rough, sometimes smooth. Penguin Island, 1600 fathoms. 



Species 4. Bathydorus hacxdifer, n. sp. 



Externally like Bathydorus spinosus. The parenchyma contains oxyhexasters and 

 discohexasters. The dermal skeleton includes numerous rough autodermal diacts and 

 monacts. In the middle of the South Pacific, 2335 fathoms. 



