REPORT ON THE ARTEROIDEA. 415 



The madreporiform body is small and subtriangular in form, the angles of the triangle 

 being rounded. It is situated rather nearer the centre than midway between that point 

 and the margin, and lies within the steep declivity of the median interradial line. The 

 striae upon its surface are very fine and show much convolution. The anal aperture is 

 distinct and excentric in position, being situated by the side of the large dorso-central plate. 



Colour in alcohol, a bleached yellowish grey. 



Locality. — Off Bahia. Depth and conditions not recorded. 



Remarks. — This species may be distinguished from Narcissia canariensis by the 

 shorter and broader rays, by the tubercular character of the abactinal plates on the 

 median keel of the rays, by the large size and convexity of the marginal plates, as well 

 as by the difference in the adambulacral armature. The two forms are, however, closely 

 allied. 



Subfamily Metrodirln.-e, Sladen, 1888. 



Genus Metrodira, Gray. 



Metrodira, Gray, Ann. and Mag. Nat. Hist., 1840, vol. vi. p. 282. 

 Scytaster (pars), Miiller and Troschel, System der Asteriden, 1842, p. 34. 



The aberrant characters of this genus have led me to place it in a distinct subfamily. 

 Its external facies and general structure appear to indicate an intermediate position 

 between the Linckiidas and Echinasteridae, but a knowledge of its internal anatomy, 

 which unfortunately the material at my disposal does not enable me to supply, is desirable 

 before the relationships of Metrodira can be more critically discussed. 



Chorology of the Genus Metrodira. 



a. Geographical distribution : — 



Eastern Archipelago : One species between the parallels of 20° N. and 20° S. 

 Metrodira subulata, from Migupou and Torres Strait, and ex- 

 tending into the Pacific. 



Pacific : Two species between the parallels of 30° (?) N. and 50° S. 



Metrodira subtilis, off the coast of China. Metrodira subidata, 

 from George Sound, New Zealand, and extending into the Eastern 

 Archipelago. 



/S. Bathymetrical range : Probably confined to Shallow water. Metrodira subulata 

 in 8 fathoms. 



y. Nature of the Sea-bottom : Metrodira subulata on Coral mud. 



