AK^EOSOMA GRACILE. 101 



Arseosoma gracile A. Ag. and CI. 



Asthenosoma gracile A. Agassiz, 1881. " Challenger " Ecli., p. 89; PI. XVIIa, figs. 1-4. 

 Asthenosoma longispinum Yoshiwara, 1897. Ann. Zool. Japon., I, p. 5. 

 Calveria gracilis Mortensen, 1903. " Ingolf " Ech., I, p. 51. 



Asthenosoma tessellatum A. Ag. and CI., 1907. Bull. M. C. Z., LI, p. 117. (Not A. tessel- 

 latum A. Ag. " Challenger " Ech., p. 88.) 



Off Japan and the Philippines ; 50-255 fathoms. 



Plates 81, figs. 3, 4; 82, figs. 5-8. 



On drying the specimen and making a more careful examination of it, 

 we find that we were mistaken in referring to A. tessellatum an Echinothurid 

 taken by the "Albatross" in 1906. The specimen is badly damaged, and 

 the uniform dark brown color like that of tessellatum misled us. In spite of 

 the peculiar color, it seems best to us now to refer the specimen to A. 

 gracile, the structure of the test and the pedicellarios agreeing well with that 

 species. But there can be little doubt that gracile and pyrocliloa are very 

 near each other and both are very near hystrvc, and the differences of color 

 are as important as any that have been pointed out. But if we make 

 color the criterion, the specimen before us cannot belong to any of the 

 three species mentioned. 



We refer to gracile with some hesitation, the small specimen from Station 

 3750, shown on Plate 81 (figs. 3-4). The arrangement of the actinal tube- 

 feet shows clearly that it is an AraBosoma, while comparison with young 

 specimens of Owstoni, the commonest Japanese form of that genus, shows it 

 cannot belong to that species. The coronal plates are much more numerous 

 than in Owstoni at the same age, and the tuberculation of the test is different, 

 the abactinal interambulacral plates being quite bare (PI. 81, fig. 4). As 

 the large pedicellarias are like those of gracile and pyrocliloa, we believe it 

 belongs to one of those species (though the color is quite bleached), and the 

 depth at which it was taken certainly indicates gracile. 



The specimens, which are 30 and 140 mm. in diameter respectively, were 

 taken by the "Albatross" at the following stations: 



Station 3750. Off Suno Saki, Honshu Island, Japan. 83-140 fathoms. 1 

 Gy. s., brk., sh.. p. 



Station 4943. Kagoshima Gulf, Japan ; 31° 24' 35" N., 130° 38' 40" 

 E. 119 fathoms. Character and temperature of bottom not recorded. 



1 The label with the specimen gives the depth as S3-89 fathoms. 



