56 THE ECHINODERMS OF TORRES STRAIT. 
has R=100 mm. The largest specimen in the Museum of Comparative Zodlogy collection 
is little more than half so large. Individual diversity is shown chiefly in the size and number 
of the tubercles; one before me from Samoa with R =50 mm. has only 10 to 12 tubercles 
on each ray but many of them exceed 2 mm. in height and in basal diameter; on the other 
hand, one from Fiji with R =58 mm. has about 35 tubercles on each ray, but the largest 
of these are only about 1.5 mm. in height and basal diameter. Koehler (l.c.) has pointed 
out that the apparently bare tip of the tubercles is really an enlarged, smooth, conical 
granule. I have found no statement in regard to the color of this species in life. 
CERTONARDOA‘! gen. nov. 
Similar to Nardoa, but the rays are actinally flat, widened, and trigonal at base, and 
the abactinal plates are arranged in regular longitudinal series on the basal part of the rays. 
As in Nardoa, the papule are in groups, but there are none on the actinal surface. 
Genotype: Scytaster semiregularis Miller and Troschel. 
Nardoa is a much more homogeneous group with semiregularis removed. This species 
approaches Narcissia in general form, but that Atlantic genus is easily distinguished by 
the isolated papule. Besides the type-species, Certonardoa contains 2 species, described 
by Koehler, based on several small specimens (R =18 to 40 mm.) taken in 10 to 53 fathoms 
on the eastern side of the Bay of Bengal. The form called by von Martens semiregularis 
var. japonica does not appear to be worthy of a varietal name. Its peculiarities are well 
within the limits of diversity caused by the method of preservation. 
Key to the Species of Certonardoa. 
Abactinal plates at base of ray quadrilateral, in regular longitudinal and transverse series; 7 to 9 longi- 
tudinal series; granules on papular areas not larger than elsewhere.................--- semiregularis 
Abactinal plates at base of ray rounded, in 3 to 7 longitudinal series which quickly become indistinct 
distally; granules on papular areas larger than elsewhere. 
Rays dorsally carinate; distal subambulacral spinelets not notably enlarged...............-.... carinata 
Rays dorsally not carinate; distal subambulacral spinelets (1 on each plate) conspicuously enlarged squamulosa 
Certonardoa semiregularis. 
Scytaster semiregularis Miller and Troschel. 1842. Syst. Ast., p. 36. 
Linckia semiregularis var. japonica von Martens. 1865. Arch. f. Naturg., 31, pt. 1, p. 351. 
Nardoa semiregularis and var. japonica Sladen. 1889. Challenger Ast., p. 412 and 788.—Ives, 1891. Proc. 
Acad. Nat. Sci. Phila., pl. vii, figs. 1-4. 
This species ranges from Java and the Moluccas to southern Japan, where it seems 
to be quite common. The color in life is said to be ‘‘gorgeous orange-red,”’ quite different 
from any species of Nardoa. In large specimens, R=90 mm. Von Martens designated 
his Japanese specimens by a varietal name because R =4.5-5r, whereas Miiller and Troschel 
state that R=7.5r. The specimen of von Martens, however, had R=55 mm., while in 
Miller and Troschel’s specimen R was about 80 mm. Moreover, aside from individual 
diversity, a specimen preserved with muscles contracted and disk high will have r much 
shorter than if the muscles are relaxed and the disk flattened. 
Certonardoa carinata. 
Nardoa carinata Koehler. 1910. Indian Mus. Ast., p. 165, pl. xv, fig. 6; pl. xvi, figs. 10, 11. 
Until the growth-stages of C. semiregularis are worked out, it can not be asserted 
positively whether carinata is the young of that species or not, but in view of Fisher’s 
(1919) figure of a young semiregularis with R only 29 mm., it seems highly improbable. 
One of the specimens of semiregularis in the Museum of Comparative Zoélogy from Japan, 
with R =55 mm., has the arms high, though not truly carinate, but the largest specimen 
of carinata had R only 40 mm. No doubt too, the degree of carination will be influenced 
by the condition when preserved and the method of preservation. The type-locality for 
carinata is the Andaman Islands, 10 to 53 fathoms. 
1 Certus =regular, orderly +-Nardoa, in reference to the arrangement of the abactinal plates at the base of the arms. 
