REPORT ON THE ECHINOIDEA—MORTENSEN a 
Station 5587; in the vicinity of Sibuko Bay, Borneo; Sipadan 
Island (W.) bearing S. 12° E., 3.8 miles distant (lat. 4°10’35” N., 
long. 118°37/12’’ E.) ; 759 meters; bottom temperature 5.72° C.; coral 
sand; September 28, 1909. Five specimens. 
Station 5589; in the vicinity of Sibuko Bay, Borneo; Mabul Island 
(NW.) bearing N. 3° W., 2.8 miles distant (Jat. 4°12’10’” N., long. 
118°388’08’’ E.) ; 475 meters; bottom temperature 7.61° C.; fine gray 
sand and gray mud; September 29, 1909. Three specimens. 
Station 5592; in the vicinity of Sibuko Bay, Borneo; Silungan 
Island (M.) bearing N. 1° W., 6.4 miles distant (lat. 4°12’44’’ N., 
long. 118°27’44’’ E.) ; 557 meters; bottom temperature 6.28 C.; green 
mud; September 29, 1909. One specimen. 
Station 5630; south of Patiente Strait; Doworra Island (N.) bear- 
ing N. 3° W., 4.5 miles distant (lat. 0°56’80’’ S., long. 128°05’00’’ 
E.); 1,040 meters; coral sand and mud; December 2, 1909. One 
specimen. 
Station 5638; in the vicinity of Bouro Island; Tifu Bay entrance 
(W.) bearing N. 17° E., 3.2 miles distant (lat. 3°47’15’" §., long. 
126°23’40”’ E.) ; 945 meters; fine gray sand; December 10, 1909. One 
specimen. 
Remarks—The specimens are on the whole in poor condition. 
Most of them are small or of medium size. Those from station 5122 
are particularly interesting, being the youngest known of this species, 
ranging from about 15 to 30 mm. in diameter. They show that the 
genital pores begin to appear at a size of approximately 25 mm. 
diameter. In the smallest specimen the genital and ocular plates are 
not yet completely separated. 
In a specimen from station 5421 I find the spines of the aboral side 
more or less thorny, thus recalling to some degree Phormosoma verti- 
cillatum; but the thorns are not arranged in whorls as is so char- 
acteristic of P. verticillatum. 
Most of the specimens are of the form designated by Déderlein as 
Phormosoma indicum, characterized by the aboral side being naked to 
a wide extent. There are, however, all transitions between such speci- 
mens, with an extensive naked part of the aboral side, to such as have 
all the plates of the aboral side provided with spines, so that I do not 
see any possibility of maintaining P. indicum as a distinct species, or 
even as a distinct variety. 
PHORMOSOMA VERTICILLATUM Mortensen 
Phormosoma verticillatum MorTeNsEN, Ann. Mag. Nat. Hist., ser. 7, vol. 14, 
p. 90, pl. 4, figs. 1, 2; pl. 5, figs. 15-17, 1904; Monograph of the Echinoidea, 
pt. 2, p. 142, pl. 8, figs. 3, 4; pl. 4, fig. 4; pl. 74, figs. 7-10, 1935. 
Phormosoma adenicum DG6ODERLEIN, Wiss. Ergebn. Tiefsee-Exped., vol. 5, Lief. 2, 
p. 134, pl. 15, fig. 3; pl. 38, fig. 4, 1906. 
