274 ART. 2. — H. MATSUMOTO : 



six or seven tentacle pores and two to those beyond ; of the 

 aboral scales there are three to the first, two to the second, and 

 one to the thnd. All the tentacle scales are flat, thin and leaf- 

 like. 



I have carefully compared this species with the description 

 and figures of Gymnopliiura cœndescens Lütken & Mortensen, and 

 have come to the conclusion that the two species agree in almost all 

 characters, e. g. the radial shields, arm combs, interbrachial ventral 

 spaces of the disk, oral shields, adorai shields, oral papillas, dorsal 

 as well as ventral arm plates, arm spines, tentacle scales, &g. The 

 only différence between my specimens and the type of G. cœndescens 

 is that in the former the scales are present all over the 

 disk, while in the latter there is a star- shaped naked central 

 space on the dorsal side. But Lyman says that, the disk of the 

 present species is " covered with a thick skin, under which 

 the thin small scales are scarcely, or not at all, distinguishable." 

 Further, Clark remarks that, his specimens " show a most 

 remarkable difference in the calcification of the disk, for while 

 several of them have the disk covering thick, with the scales 

 hardly distinguishable, as in Lyiman's type, others have it much 

 thinner with the scales evident, while still others have a greater 

 or less part of the disk covered by a naked skin, the calcification 

 being confined to the vicinity of the radial shields and to the 

 interradial margins," and that " the gradation between the two 

 extremes is so complete that there can be no doubt that the 

 amount of calcification is an individual and not a specific or even 

 a local matter." I therefore look upon G. ccerulescens as a 

 synonym of the present species. 



