52 PROCEEDINGS OF THE ACADEMY OF [Feb., 



hsemal canal and genital bursse communicating with each 



other Trichasterin^. 



aa — Lateral arm plates of opposite sides meeting each other in 

 the ventral median line, distal ones not projecting ven- 

 trally like hanging rods; arm spines unequal, the adradial 

 one being much larger and longer than the abradial and 

 often clavate; perihsemal canal and genital bursse not in 

 communication; arms simple Asteroschematin^. 



Subfamily 1. ASTERONYCHIN^ nov. 



Disk very large, arms very slender and unbranched. A single 

 madreporite is present. Perihsemal canal entirely closed. Peri- 

 toneal cavity divided into five compartments by the interradial 

 attachments of the gastral pouches to body wall. Genital bursse 

 separated from the perihsemal canal and the peritoneal cavity, but 

 the pairs of the same radius communicating with each other, the 

 communication passing above the outer end of the oral frames and 

 the first vertebra, just outside the perihsemal canal. Lateral arm 

 plates of opposite sides separated by the comparatively large ventral 

 arm plates. Arm spines, 3-8. 



This subfamily includes Asteronyx and Astrodia. 



Subfamily 2. TRICHASTERIN.E nov. 



(Characters as given above in key.) 



This subfamily includes Ophiuropsis, Astroceras, Trichaster, 

 Sthenocephalus and Euryala. 



Subfamily 3. ASTEROSCHEMATIN^E Doderlein, 1911 (emend.). 



(Characters as given above in key.) 



This subfamily includes Asteroschema (including Ophiocreas) and 

 Astrocharis. 

 Asteroschema tubiferum Matsumoto. 



1911, Dobuts. Z. Tokyo, 23, p. 617 (in Japanese). 



This species strongly resembles A. rubrum Lyman, but differs 

 chiefly in the much coarser granules of the arm bases, in having 

 tentacle tubes for some ten basal tentacles, and in the relatively 

 longer and stouter arm spines. Three or four granules lie in 1 mm. 

 on the dorsal side of the free arm base. Oral tentacle pores, as 

 well as tentacle pores of some ten basal arm joints, open by means 

 of cuticular tubes, each of which, except that of the oral tentacle 

 and the first arm tentacle, is attached to the adradial arm spine on 

 its adradial side. The arm spines become longer and stouter distally, 



