84 ART. 2. — H. MATSUMOTO : 



grannies of the disk, and in the less number of arm joints con- 

 tained in a shaft. In the last characters, A. arctos rather resem- 

 bles A. nigra from Zanzibar and Hirado Strait, Japan. 



This species is common in the shallow waters aronnd Misaki,. 

 and occurs in the same localities with the foregoing species. 



Astroboa glohifera (Döderlein). 



AstropJiyton glohi/ernm : Döderlein, Zool. Auz., XXV, 1902, p. 324. 

 Astroboa glohifera: Döderlein, Abh. Matli.-Phys. Kl. K. Bayer. Akad. 

 Wiss., Suppl.-Bd. I, 1911, p. 51, PI. n, figs. 8-9 ; PI. VU, figs. 7 & la. 

 One specimen ; off Kotsu-jima, Izu. 

 Sagami 8ea ; 150-200 m. (Döderlein). 



Key to genera of Astroto^ninœ, 



A — Interannuli of the arm covered with two rows of coarse granules ; 



arms simple. 

 a — Disk more or less closely beset with thorny tubercles or spiny 



granules Astrothamnus. 



aa — Disk covered with rounded plates, which are surrounded by belts of 

 granules. 



I — Disk plates irregular in size ; two or three arm spines 



Astrothrombns. 



hh — Disk plates regular in size ; three to seven arm ^^ines., Astrothorax^ 

 AA — Interannuli of the arm covered with many rows of fine granules ; 

 disk also covered with fine granules. 



c — Arms simple Asfrotonia^ 



cc — Arms divided a few times near the tip Aatroclon. 



Astrothamnus Matsumoto, 1915 



Disk divided into ten radiating lobes by radial and interradial 

 furrows, closely covered with coarse, thick granules, which are 



