382 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



a'. Some of the abactinal plates nearly or quite hemispherical, while others are 



less markedlj' convex ; or else plates variably convex and some others 



here and there in the form of hemispherical, subcylindrical, or subconical 



tubercles, as high as their breadth at base. 



6\ Abactinal tubercles very prominent, acorn-shaped, or conical with the tip 



bare (rarely completely granular). Only 1 row of subambulacral spines, 



the granules on outer part of adambulacral plates being equal to those 



of the actinal surface aegyptiaca Gray. 



6*. Abactinal tubercles entirely granular; outer granules of adambulacral 

 plates larger than adjacent actinal intermediate granules, so that in a 

 measure the adambulacral armature grades into that of the actinal sur- 

 face, 

 c*. Abactinal plates very numerous, more nearly equal, some more con- 

 spicuously convex than others, the most prominent, hemispherical, 



but not so high as wide tuberculata, p. 384. 



c". Abactinal plates very unequal in size, larger ones forming thick sub- 

 conical or dome-shaped tubercles covered with granules. 

 d\ Abactinal tubercles numerous, 30 or 40, more cylindrical in form. 



frianti, p. 385. 

 (Z". Tubercles fewer, usually about 10 to 15, some of the larger subellipti- 

 cal and oriented transversely, relatively larger than in frianti, lower 

 in proportion to width, and evenly rounded or dome-shaped. 



tunwlosa. p. 386. 



NARDOA LEMONNIERI Koehler. 



Nardoa Le Monnieri KoEHLEaj, 1910a, p. 161, pi. 18, figs. 1 and 2. 



Koehler^ has given figures and a detailed description. In the 

 Philippine specimen, K=:110 mm., r=15 mm., R=:7 r; breadth 

 of ray at base, 16 mm. to 20 mm. If the dorsal plates are denuded, 

 their contour is irregularly scalloped and short-lobed, the arcuate 

 indentations being on the margin bordering papular areas. Accord- 

 ing to Viguier's figure of ^V. novae-caledoniae (1879, pi. 9, fig. 8) 

 the dorsal plates are entire. The actinal series of papular areas, be- 

 tween the inferomarginals and actinal intermediate plates comprises 

 only 6 to 9 areas, and is therefore shorter than in the type. There 

 are usually 9 marginal mouth spines, and 6 in the parallel suboral 

 series. >. 



Type-locality. — Andaman Islands. 



Distribution. — Known only from Andaman Islands and Sulu 

 Archipelago. 



Specimen examined. — Station 5159, Tawi Tawi Group, Sulu 

 Archipelago (off Tinakta Island) , 10 fathoms, coral sand ; 1 specimen. 



Remarks.— T\\Q nearest relatives of this species are A'', mollis de 

 Loriol (New Britain), N. novae-ccdedoniae Perrier (New Caledonia), 

 and N. galatheae Liitken (Nicobar Islands and Togean Islands, Cele- 

 bes). N. galatheae is not well understood. It is near N. mollis ac- 

 cording to de Loriol, who mentions as the only differences that gala- 

 * — — 



» 1910O, p. 161, pi. 18, figs. 1 and 2. 



