\\0 Mr. A. Alcock on 



third row of plates throughout tlie ray, and between the third 

 and fourth row of idates in the basal fourth of the ray, there 

 arc niii:utc perforations (seen only in the dried s].ccimcn) 

 which appear to be too small for the jiassage of ])ai)uliv. 



Adambulacral plates very small, but extending high up 

 into the furrow ; each plate has two short transverse scries ot 

 spinclets, and every alternate plate has a prominent intra- 

 ambulaeral ridge bearing three stout spinelets, of which the 

 innermost is furnished with a large pedicellaria emerging 

 from a cluster of small pcdicellariai. Mouth-plates witii long 

 needle-like spines and large clusters of pedicellariae. 



Tube-feet quadriserial. 



:Madreporiform jdate very small, with coarse peach-stone 

 sculpturing. 



Colour in life orange-pink. 



Laccadive Sea, 1043 fathoms, green mud. 



44. Zoroaster zea, sp. n. 



Rays 5. R = about 12 r. R=144 millim. iii 

 the type specimen. 



Disk semicircular, flat-topped, well raised above the rays, 

 from which it is delimited by a circumferential series of 

 massive oval or substellate plates, arranged exactly as in 

 Z. GUesii and Z. sqvamnis, with small plates intervening. 

 All the plates are quite smooth and membrane-clad, but the 

 small intervening plates bear each a small coarse spine ; the 

 intervals between the plates show distant papula3 and pedi- 

 cellariie, tlie last often in pairs. 



Kays long, rigid, subcylindrical, tapering, witli thirteen 

 longitudinal parallel serie.«} of Indian-corn-like or bead-like 

 meml)rane-clad plates, which also fall into transversely 

 ])arallel scries. A single ray, viewed abactinally, has much 

 tiie apiicarance of a seed-spike of maize. The plates are 

 disposed as follows: — (i.) a mid-radial row of slightly 

 enlarged plates, flanked on each side by a deep furrow, in 

 which lies (ii.) a discontinuous row of minute ])latelets con- 

 cealed by membrane, and only revealed either by a small 

 pedicellaria or by a coarse spikelet which they sometimes 

 bear ; and outside these (iii.) six rows of plates, decreasing in 

 size and inclining to imbricate actinally, of which the three 

 abactinad rows are, like the mid-radial row, quite naked and 

 unarmed, while the three actinad rows are tliickly covered 

 with membrane clad squamous spinelets and bear a median 

 spine and sometimes a marginal pedicellaria. Long papulae 



