206 MB. W. PEECY SLADEN ON" THE 



feet arranged in simple pairs. Ainbulacral spinelets 5, forming 

 transverse combs. The two innermost spines much smaller than 

 the rest, and standing parallel with the furrow, rather in advance 

 of, or aboral to, the other three, which are disposed across the 

 broad adambulacral plate, articulated on more or less definite 

 tubercles, and forming a series at right angles to the furrow. 

 The middle spine is longest. The whole series webbed together 

 with membrane deeply indented between the radiating spinelets, 

 but not nearly so much as in Marsipaster spinosissimus. 



Mouth-plates broad, having wide lateral expansions, and with 

 an elevated ridge along their line of junction, developing a pro- 

 minent peak aborally and a rounded point inward. The arma- 

 ture consists of three long, robust mouth-spines placed on the 

 horizontal margin of each plate, the innermost spine largest and 

 longer than the ambulacral spinelets, the outermost less than 

 half its size, and sometimes accompanied by an additional dimi- 

 nutive spinelet. The inner spines stand well away from the adoral 

 point of the united mouth-plates, which becomes in consequence 

 rather conspicuous. Immediately behind or aboral to the mouth- 

 spines proper is a single superficial or secondary mouth-spine, 

 smaller than the long mouth- spines. The three mouth-spines of 

 each plate are webbed together by a semitransparent membrane 

 deeply indented between ; and the secondary spine is united to the 

 innermost spine by a continuation of the web. The long, inner- 

 most spines are directed towards the centre of the mouth, where 

 they almost meet, the other spines radiating slightly outward from 

 this. The iirst, or most adoral, comb-series forms a widely ex- 

 panded semicircular fan, the web being continued and attached 

 to the prominent aboral peak of the mouth-plates. 



Actino-lateral spines robust, but short ; character of the fringe 

 destroyed, probably more or less distinct along the rays ; spines 

 not reaching to the margin in the interbrachial angle, but merged 

 in the membrane of the ventral floor. The margins of the rays 

 and disk are well rounded and regularly covered with the intra- 

 paxillar tissue continuous from the disk ; indeed the greater 

 part of the ventral portion of the interradial space is thus pro- 

 vided. 



Colour, in alcohol, brownish grey. 



Station 299. Lat. 33° 31' S., long. 74° 43' W. Depth 

 2160 fms. ; bottom temperature 1°-1 C. ; grey mud. 



