250 AET. 2. — H. MATSUMOTO : 



flat disk, in the peculiar shape of the oral shields, in the soldered 

 oral papillse, in the rudimentary dorsal, as well as ventral, arm 

 plates, in the very small tentacle pores, which are limited to 

 the proximal arm joints, and in the very few tentacle scales ; and 

 from Antliophiura in the entire central plate and in the presence 

 of the genital scales and arm combs. 



Key to Japanese species of Aspidophiura, 



A — The six primaries each with a small but conspicuous central boss ; 

 radial shields about as large as the radiais ; ventral arm plates 

 rapidly diminishing in size outwards ; arm spines longer than half 

 the corresponding arm joint ; no tentacle scale beyond the disk . . . . ' 



loatasei. 



AA — The six primaries without a central boss ; radial shields distinctly 

 larger than the radiais ; ventral arm plates very slowly diminishing 

 in size outwards ; arm spines shorter than half the corresponding 

 arm joint ; single tentacle scale to each pore beyond the disk .... 

 forhesi. 



Aspidophiura watasei Matsumoto. 



Aspidophiura luatasei : Matsumoto, Proc. Acad. Nat. Sei. Philadelphia, 

 1915, p. 77. 



One specimen; off Misaki, Sagami Sea. One specimen; 

 Uraga Channel. 



Diameter of disk 5 mm. Length of arms unknown, but 

 probably about twice the disk diameter. Width of arms at base 

 1.3 mm. 



Disk circular, very flat. The area inside the radial shields is 

 mostly occupied by the six stout primary plates, and the inter- 

 radial spaces of the dorsal surface each by two stout plates. The 



