JAPANESE ASTEEOIDEA. 457 



Strassburg, the well known pioneer in the study of Japanese 

 echinoderms. 



Specimen in S.C. 



Oreaster niaf/nißctis, n sp. 

 (PI. XV, %. 237-240.) 



I have only one dried specimen of this species in a rather 

 unsatisfactory condition, but the essential characteristics can all 

 be made out, and there is no doubt in my mind that it represents 

 a new species. To judge from the descriptions of preceding au- 

 thors it appears to present some points of resemblance to 0. 

 australis Lütken and 0. loestermanni Lütken, but the marginals are 

 entirely destitute of tubercular formations, the ventrolaterals are 

 covered with very coarse granules which have a slight tendency to 

 become spiny, and only a few of the abactinal plates are produced 

 into tubercular structures. 



The specimen before me is very large, being the largest 

 specimen of Oreaster that has come into my hands so far ; r^95, 

 R = 220 mm., giving the radial ratio 2.3. The entire body is depress- 

 ed, being level on the actinal, and lightly inflated on the abactinal 

 side, in the centre of which there is a depression surrounded 

 by five adcentral, radial tubercles. The interbrachial arcs are 

 broadly open ; in each there can be seen an almost straight stretch 

 forming the margin of the disk. The arms are fairly long and 

 perfectly rounded on the abactinal side, while on the actinal side 

 it is plain, so that they would present a semicircular outline in 

 cross section. The colour of the dried specimen is greyish brown, 

 being lighter on the actinal side. 



