246 ABT. 2. — H. MATSÜMOTO : 



the central boss on the primary plates, in the much narrower 

 dorsal arm plates and in the much narrower free portion of the 

 arms. Lately, Kœhlek has described A. cavellœ from the vicinity 

 of the Cape of Good Hope, from which the present species differs 

 chiefly in the mnch shorter and smaller infrabasals, in the much 

 narrower basais and interradiais, in the radiais being not distinct- 

 ly pentagonal but shaped like maiden hair, in the scarcely joined 

 radial shields, in the absence of the central boss on the primary 

 plates, in the much narrower dorsal arm plates, in the much 

 smaller madreporic shield, in the absence of the ordinary oral 

 shields, in the longer adorai shields, in the oral plates being in 

 contact to a less extent, and in the much narrower free portion 

 of the arms. On the whole, A. permira, A. cavellœ and Chun's 

 AstropJiiura (there is some possibility that it belongs to one of 

 the two first mentioned species) appear to me to be nearer to 

 one another than any of them is to the present species. This 

 fact may be correlated with the geographical separation of the 

 present species from the others, which occur near together. 



Haplophiura Matsumoto, 1915. 



Disk high, much elevated above the arm bases, covered with 

 rather large plates, among which the primaries are very prominent. 

 Eadial shields stout, joined in pairs. Interbrachial ventral surfaces 

 covered with fine granules. Genital slits indistinct. Oral papillœ 

 soldered together. Teeth in a single vertical row. Dental papillœ 

 absent. Arms short, stout. Arm plates convex. First ventral 

 arm plate larger than tlie following. Few, very small arm spines. 

 Tentacle pores, including the second oral tentacle pore, which 

 opens outside the oral slit, entirely free of scales. 



