MONOGRAPH OF JAPANESE OPHIUROIDEA. 29 



Earyale Lamakck, 1816. 

 Subfamily 3. Aster oschematlnce milii, 1915. — Disk very small 

 and arms very stout ; one madreporite to each interradius ; peri- 

 hœmal canal closed ; genital bursae free from the perihsemal canal 

 or from each other ; lateral arm plates of either side meeting each 

 other in the ventral median line, distal ones not projecting ventrally 

 in the form of hanging rods ; two unequal arm spines on each 

 plate. 



Asteroschema Œested & Lütken, 1856.^^ 



Astrocharis Kœhlee, 1904. 



Astrogymnotes Claek, 1914. 

 A very characteristic feature of the Asteronychiuœ is the posi- 

 tion of the genital scales, which articulate with the genital plates 

 near the inner ends of the latter, while in the other subfamilies, 

 the scales articulate with the plates near the outer ends of the 

 latter. In Aster onyx loveni Müller & Teoschel, the radial shields 

 are composed of several lamellar secondary plates, which overlap 

 and fuse together. The wall of the gastral cavity is attached to 

 the body wall at the central part on the dorsal side of the disk 

 and along the interradial lines above and below, so that the. peri- 

 toneal cavity is perfectly divided into five radial compartments, 

 which are filled up by the folded generative glands. The peri- 

 heernal canal is entirely closed. The genital bursso are very spacious, 

 but do not communicate with the perihaemal canal, and are 

 separated fi'om the peritoneal cavity by a thin, folded membrane. 

 Each radial pair of tlio bursa? however communicate with each 

 other just above the outer end of the oral frames and the first 



1) Including Ophiocreas Lyman, 1869. 



As far as the external characters are concerned, Ophiocreas adherens Studer, 1884, and 

 Asteroschema kcehleri Dödeblein, 1898, appear to be referable to the Tr'ichasterlnœ ; they may 

 possibly be young forms of Aslroceras, 



