1915.] NATURAL SCIENCES OF PHILADELPHIA. 73 



Numerous specimens; Sakurajima, Kagoshima Gulf. 



This sjiecies is very near Ophionephthys phalerata Lyman, but 

 differs from it in the much larger radial shields, in the not oval but 

 pentagonal oral shields, in the adoral shields, which are not in contact 

 with each other, in the longer oral plates, in the dorsal arm plates 

 being in contact with each other, in the ventral arm plates being 

 separated from each other and not very wide on the basal joints, and 

 in the not cylindrical, but flattened, thorny arm spines. 

 Amphiura aestuarii sp. nov. 



Diameter of disk, 6 mm. Length of arms, 75 mm. Width of 

 arms at base, 0.8 mm. Disk five-lobed, with concave interbrachial 

 borders, covered by a soft, naked skin, except along inner and abra- 

 dial borders of radial shields, where it is covered by fine, imbricating 

 scales, arranged in four or five rows on inner border, but in only 

 one on outer part of abradial border. Naked part of radial shields 

 large, pear-seed-shaped, more than half as long as disk radius, more 

 than twice as long as wide, hardly in contact without, slightly diver- 

 gent within. Genital slits long. Genital scales not very distinct. 



Oral shields rhomboidal, or pentagonal with a very short inner 

 side, outer angle much rounded; wider than long. Madreporic 

 shield much larger and almost circular. Adoral shields triangular, 

 with concave inner side, tapered within, where they do not meet. 

 Two pairs of oral papillae to each jaw; apical ones oval and very 

 stout; distal ones conical, obtuse, arising from adoral shields. Teeth 

 stout, truncate. 



Dorsal arm plates transversely elliptical, twice as wide as long, 

 successive plates in contact with each other. Lateral arm plates 

 not very prominent, almost covered by arm spines, not meeting 

 above or below, not in contact on sides, but separated by naked spaces. 

 First ventral arm plate very small, pentagonal or quadrangular, 

 wider within than without; tho5e beyond, quadrangular, with 

 convex inner side, notched distal margin, and rounded distal angles; 

 wider than long, except basal one or two; not in contact, but sepa- 

 rated by a narrow space, where ventral ends of lateral arm plates 

 are wedged in. Arm spines five, on basal joints, but four in middle 

 part of arm, subequal or lower slightly longer, nearly equal to, or 

 a little longer than, corresponding arm joint; conical and obtuse on 

 proximal joints, but flattened distally; next to lowest spine especially 

 flattened and rather spur-shaped, with numerous thorns on its much 

 flattened tip; lowest spine (as well as second above it) also more 

 or less thorny at tip. 



