JAPANESE ASTEROIDEA. 91 



are slioi-t, clavate and skin-covered. Marginal, actinal intermediate, and 

 adambulacral plates obscured by a thin soft skin. Continuous narrow deep 

 grooves extend between marginal plates, across intermediate area, and 

 between consecutive adambulacral plates. These are overhung on either side 

 by a fold of skin embedded in which are numerous flattened spinelets, as 

 in the lamellae of typical cribriform organs. Between special raised ridges 

 of marginal plates these furrows are deex^er and V-shaped with five to seven 

 superimposed lamellas on either side. Marginal plates eleven to twenty-, in 

 each series, from median interradial line to extremity of ray. A single short 

 conical spine at upper end of each superomarginal, and another similar one 

 on each inferomargiual on the actinolateral margin of ray. Adambulacral 

 plates with an oblique series of tln-ee to five sharp short skin-covered 

 spines, and on aboral outer corner a similar, usually shorter sx^ine, 

 covered with the general investment of actinal sm-face. ' Mouth plates 

 prominent ; along free margin, about six sj^ines Hke those of adambula- 

 cral and at inner end of yAsiie a single more x)i"oniinent sx)ine ; two 

 or tlu'ee short conical tubercles usually stand in a series on either side 

 of median suture, these sometimes as long as fmTOw spines. Superambula- 

 cral plates present. 



" Description. — ^No adequate description of this species is readily availa- 

 ble. With the amx)le material at my disx)osal it seems well to give a 

 description and at the same time to x)oint out some of the most prominent 

 of the variations. Instead of placing tliis last, a separate subhead is given 

 to each category of characters and the variations considered at once. 



" This a remarkably variable sx)ecies, es^^ecially in the length of the 

 rays, and their width, and in the general faciès of the animal. Practically 

 all of the most diverse variations may occur in examples from a single 

 station, and they are thus not due to locaHty. As slender and broad armed 

 forms occur among the smaller specimens this difference is not due to age. 



" Pro2)ortions. — A striking series of four nearly equal sized sx)ecimeus 

 from stations 4235 illustrates admirably the difference in form, measm-ements 

 being given in the accomjDanying table. 



" Measiu'ements of CtenocUsciis crtsjKitKS. 



