85 



distinctly crenulate, and there may be indications of a stellate structure at ttieir 

 base. The secondary tubercles are rather' numerous, in larger specimens very 

 crowded, forming more or less distinct vertical and horizontal series; especially 

 inside the primary series there is a vertical series of secondary tubercles, which 

 may be almost as large as the primary ones; they may be more distinct in the 

 ambulacra than in the interambulacra. The pores are very small, disposed in a 

 very nearly straight series, close to the edge of the area (only at the ambitus a 

 little distant from the edge in the largest specimen), no tubercles being found out- 

 side the pores. The poriferous zone is very narrow, only ca. V? — Vs as broad as 

 the interporiferous zone. The ambulacral plates are as high as the interambulacral 

 ones, their number being the same. The small pits at the outer edge of the area 

 are very indistinct or quite wanting. 



Apical system (PI. II. Fig. 6). The genital plates show the peculiar feature 

 of the outer part with the genital opening being separated from the inner part by 

 a distinct, mostly curved line, so that it seems as if the plate were divided in two 

 parts, which is, however, not really the case. Sometimes the transverse line is 

 obscured by tubercles, but never, so far as my experience goes, on all the plates; 

 on the madreporite it is never distinct. The outer part of the genital plates is 

 mostly darker coloured than the inner part. There is a circle of tubercles along 

 the inner edge. The genital opening is placed near the outer edge. The ocular 

 pore is placed on the outer edge of the rather thick ocular plate and cannot be 

 seen from above; the part of the plate outside the pore is white and looks like a 

 small distinct plate. The depression between ocular and genital plates is small and 

 indistinct. The anal opening is not central; there is a distinct anal plate. 



The buccal membrane contains rather many bihamate spicules; the plates 

 along the oral edge may be rather numerous (a fact which depends on the size of 

 the animal, in all probability). The buccal tubefeet may sometimes be placed one 

 outside the other; in one specimen I have found the one tubefoot wanting in one 

 of the pairs, a fact which is not without interest, considering the curious instance of 

 PI. Döderleini having all the buccal tubefeet constantly unpaired. — The spines are 

 short (Vs— V4 of the diameter of test), smooth, not thickened at the point; the 

 actinal spines are not widened or curved. — The globiferous pedicellariæ are quite 

 similar to those of PL ruber, and reference may simply be made to the figures given 

 thereof for that species. The triphyllous pedicellariæ are quite similar to those of 

 bothryoides. The ophicephalous pedicellariæ do not present peculiar features. Bi- 

 hamate spicules may be rather numerous in the walls of the intestine. — The colour 

 of the test is gray or grayish-yellow, with some white spots; the pore areas are 

 white. The spines are faintly greenish or whitish with a faint red tint at the base 

 and a darker band in the outer part. 



Specimens of this species have come from the following localities: Formosa- 

 Channel, 35 fathoms (Suenson); Lat. 32° 22' N., long. 128^^ 42' E., 170 faths. (Suenson); 



