18 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 
Genus ARAEOSOMA Mortensen 
ARAEOSOMA CORIACEUM (A. Agassiz) 
PLATE 1, Ficure 1 ‘ 
Asthenosoma coriaceum A. AGASSIZ, Challenger Reports, Zoology, vol. 3, pt. 9, 
Echinoidea, p. 88, pl. 17a, figs. 5-7, 1881. 
Araeosoma coriaceum MortENSEN, Jngolf Echinoidea, pt. 1, p. 53, pl. 11, fig. 15; 
pl. 12, fig. 27; pl. 14, fig. 5, 1903; Monograph of the Echinoidea, vol. 2, p. 241, 
pl. 32; pl. 33; pl. 34; pl. 79, figs. 10-15, 1935. 
Locality—Station 5446; eastern coast of Luzon; Atalaya Point, 
Batag Island, bearmg S. 64° E., 5.3 miles distant (lat. 12°48’51”’ N., 
long. 124°59’18’’ E.); 540 meters; green mud; June 3, 1909. One 
specimen. 
Remarks.—That this specimen should be referred to Araeosoma 
coriaceum seems rather certain. It is this specimen that is figured in 
my Monograph on plates 33 and 34. Some minor differences in 
regard to the pedicellariae are probably only apparent. I do not 
find in this specimen any pedicellariae exactly like the form figured 
in my Zngolf report (pl. 14, fig. 5), but the smaller tridentate ones 
are otherwise exactly as in the type of coriacewm. Then I find in the 
present specimen a large form of involute pedicellariae (pl. 1, fig. 1) 
that has not been observed in the typical coriaceum. These two nega- 
tive characters cannot, of course, prove the Albatross specimen to be 
a different species, there being no other characters to distinguish 
them. It may be particularly mentioned that the hoof of the oral 
primary spines is small and broad in the Albatross specimen as it is 
in the type. 
The color of the present specimen is a uniform dark gray. 
The aboral plates are straight, as in one of the original specimens. 
Agassiz in his preliminary report on the Challenger Echinoidea 
gave this species from station 204 off the Philippines (lat. 12°43’ N., 
long. 122°10’ E.) in 100 fathoms, whereas in the final report he gave 
it only from off the Fiji Islands. The specimen from station 204 
seems to have disappeared. The finding of the species by the Alba- 
tross in the Philippine Sea makes it probable that the Challenger 
specimen from this region may have been a true A. coriaceum. 
The intestine of this specimen, which I have stuffed in order to 
make it assume its real shape, proved to contain mainly bits of land 
plants, though also a little bottom material. 
ARAEOSOMA TESSELLATUM (A. Agassiz) 
Asthenosoma tessellatum A. AGAssiz, Challenger Reports, Zoology, vol. 3, pt. 9, 
Echinoidea, p. 88, pl. 12a, figs. 14, 15; pl. 19a, fig. 1; pl. 19b, 1881. 
Araeosoma tesseliatum MortTENSEN, Ingolf Echinoidea, pt. 1, pp. 54, 64, pl. 18, 
figs. 5, 6; pl. 14, fig. 15, 1903.—pE MetserE, Siboga Echinoidea, p. 35; pl. 13, 
