REPORT OF THE ECHINOIDEA—MORTENSEN hy 
considerable variation in the outline of the periproct, from about as 
broad as long to longer than broad. Three or four interambulacral 
plates surround the periproct. The plate No. 4 of ambulacra Ia and 
Vb is traversed by the subanal fasciole, which includes three inter- 
ambulacral plates. The test is densely covered by miliary tubercles 
among which rise the primary tubercles, scattered without order, few 
on the aboral side, but larger and more numerous toward the posterior 
end and along the sides of the test, as well as on the oral side, excepting 
the posterior ambulacra, where they are again smaller. 
Of pedicellariae only the tridentate, ophicephalous, and triphyllous 
types are found, none of the globiferous and rostrate types. The tri- 
dentate pedicellariae have broad, simply leaf-shaped valves, with the 
edges of the basal part irregularly serrate; the largest examples meas- 
ure 0.7—0.8 mm. in length of head, with a very short neck. Ophicephal- 
ous and triphyllous pedicellariae are not peculiar. 
Color a light brownish or whitish. 
Remarks —¥rom the only other species of Plewechinus with four 
genital pores, the sub-Antarctic P. nordenskjold?, the present species 
differs markedly by the two anterior pores being situated in a single 
plate, the fused genitals 2 and 3; in P. nordenskjéldi these plates are 
separate, not fused. 
This is much the largest of the species of Plewechinus, none of the 
other species exceeding 20 mm. in length. 
The genus Plewechinus has thus been found to be represented also in 
the Malay region and may be expected to have a world-wide dis- 
tribution; the three other species known are from the Gulf of Cali- 
fornia (P. cinctus), the North Atlantic (P. hirsutus), and the sub- 
Antarctic (P. nordenskjoldi). 
Family ECHINOCORYTHIDAs 
Genus STEREOPNEUSTES de Meijere 
STEREOPNEUSTES RELICTUS de Meijere 
Stercopneustes relictus DE MrtsEeRE, Siboga Echinoidea, p. 148, pl. 5, figs. 41-43; 
pl. 19, figs. 390-893; pl. 20, figs. 394-407, 1904.—MorrENsEeN, Annot. Zool. 
Japon., vol. 12, p. 393, 1930. 
Localities—Station 5116 (lat. 18°41’ N., long. 120°47’ E.); 622 
meters; January 20, 1908. One specimen. 
Station 5425 (lat. 9°38’ N., long. 121°11’ E.) ; 907 meters; March 
31,1909. One specimen. 
Station 5527 (lat. 9°12’ N., long. 123°44’ E.) ; 741 meters; August 
11,1909. Two specimens. 
Remarks.—The specimen from station 5425 is 90 mm. long, 85 mm. 
broad, and 67 mm. high, the largest specimen known of this species. 
