102 Mr. A. Alcock on 



been ])vonouncecl by Mr. Slaclen to be merely a synonym of 

 Nectria ocellifera (Lamarck). 



The single specimen is I'rom the Andaman Sea, 238 to 290 

 fathoms. 



Family Zoroasteridse. 



ZOKOASTER, Wyville Thomson. 



37. Zoroaster Alfredi^ sp. n. 



Rays 5. E = 9 r. R = abont 190 mi Him. in the 

 type specimen. 



Disk small, hemispherical, tumid above the tumid rays ; 

 lays long, narrow, tapering, subcylindrical to cylindrical. 



Abactinal surface of disk with large distant, subhexagonal, 

 or substellate primary radials and interradials surrounding a 

 large dorso-central plate, and with numerous small intervening 

 plates ; all the plates are closely covered with simple or 

 grooved or bifid membrane-clad spinelets, and the large 

 hollows between neighbouring plates contain each a group of 

 pa]3ul« and a group of pedicellarite, one of which is of con- 

 spicuous size, being about as big as a grape-stone. 



The rays have a longitudinal mid-radial row of large 

 subhexagonal plates co-serial with tJie large primary plate of 

 the apical system, and on each side of it and parallel with it 

 six (in the interbrachia seven, at the end of the rays five) 

 rows of smaller plates, which also form transversely parallel 

 series, the lowest row articulating with the cramped adambu- 

 lacrals ; all these plates are closely covered with simple or 

 grooved membrane-clad s])inelets and pedicellarite, and bear a 

 centrally-placed spine, which is small, erect, and often obso- 

 lescent in the plates of the abactinal rows, but large and 

 acumbent in the four lower rows on each side, gradually 

 increasing in size from above downwards; the large hollow 

 intervals between neighbouring plates, which, in consequence 

 of the symmetry of the plates themselves, also fall into longi- 

 tudinally and transversely parallel series, contain groups of 

 pedicellaria^, one of which in each group is conspicuously 

 enlarged, and (except between the lowermost two rows of 

 plates) from one to three papula3. 



The adambulacral plates extend vertically far upwards into 

 the furrovv, and the whole system is so cramped that the two 

 middle tube-feet of each row are quite perceptibly atrophied 

 by pressure ; every alternate plate has a strongly salient 

 intra-ambulacral ridge, upon which stands a row of three or 



