22 AET. 2. — H. MATSUMOTO .* 



lying within the genital plates, where they present elongated oval 

 outhnes. The genital plates and scales are distinguishable, though 

 they are covered by the skin. 



The oral skeleton can be observed by drying the specimens. 

 The oral shields are transversely oval, or rather rhomboidal, with 

 an obtuse inner angle, and wddely rounded outer and lateral angles. 

 Adorai shields small, curved abradially as a whole, tapering in- 

 wards, where they do not meet each other. Four oral papillae on 

 either side, flat, thin, translucent, and finely serrate along the free 

 edge. Five to seven teeth, short, flat, with rounded, finely serrate 

 or nearly entire end ; the uppermost one is longer and more or 

 less conical. Below the first oral tentacle pore in the oral slit, 

 occur one to three spiniform papilla). 



Arms slender, covered by a thick skin. The arm plates and 

 vertebra3 can be observed by drying the specimens or by boiling 

 an arm piece in potash. The vertebrae are rhomboidal when view- 

 ed from above, much wider than long, with a conspicuous median 

 groove. Between them, there are, in the proximal parts of the 

 arms, a few irregular scales, perhaps representing the dorsal arm 

 plates. Lateral arm plates subventral, meeting below, where they 

 are soldered together and with the ventral arm plates of the 

 corresponding joints. The ventral arm plates are eight- sided ; two 

 sides embracing a conspicuous notch at the outer end of the plate ; 

 inner sides the longest, straight, meeting each other in a wide 

 angle ; inner lateral sides concave, corresponding to the tentacle 

 pores ; wider than long, widest at the outer ends of the tentacle 

 pores. Three or four arm spines, short, stout, conical, blunt, 

 enclosed in skin, rough at the end ; the uppermost one is the 

 longest, nearly as long as the corresponding arm joint, somevfhat 

 isolated from the rest which are near together. The arm spines 



