STARFISHES OF THE PHILIPPINE SEAS. 105 



mediae with edge to furrow, and 8 or 10 mflch shorter, clavate and 

 thick, pulpy, papilliform subambulacral spines, in 2 series, and uni- 

 form with the intermediate spines or spinelets. The armature is 

 very similar to that of gotoi, but is a trifle shorter. The first adam- 

 bulacral is much compressed with 18 to 20 spines in 2 closely ap- 

 pressed transverse series. 



Mouth plates similar to those of gotoi in form and armature. 

 There are 4 prominent flat truncate spatulate teeth at the inner 

 angle of the combined plates, a w^ide median suture, and along the 

 surface of each plate a double series of spines to the outer end, 

 those of the inner or superficial series being subglobular to clavate, 

 and the marginal spines being smaller and strap-shaped, closely ap- 

 pressed against the superficial spines, and of equal length. The 

 marginal series extends to the outer end of plate, although the outer 

 spines are widely spaced. In the foregoing species the marginal 

 spines are considerably shorter than the superficial, which are less 

 stubby, and the series does not occur on the outer fourth of the 

 plate. On some plates of the present species it is lacking on the 

 outer fourth, so that the character is of little value for specific 

 distinctions. 



Madreporic bod}' small, a little over its own diameter from mar- 

 ginal plate, with a few coarse transverse (interradial) striae. A 

 large paxilla stands at the adcentral side. 



Type— C^i. No. 30518, U.S.N.M. 



Type-locality — Station 5632, south of Batjan Island, Molucca 

 Islands (lat. 1° S.; long. 127° 50' E.), 845 fathoms. 



Distribution. — Known only from the type-locality. 



Specimens examined. — Two; the type and specimen from station 

 5631, same locality, 809 fathoms, green mud. 



Remarks. — While this species in a general way resembles Ps. gotoi 

 from off Luzon, it differs very markedly in the structure of the mar- 

 ginal plates and their armature, and in having smaller, less close-set 

 paxillae. and shorter actinal spines generall5^ The less extensive 

 distribution of actinal. intermediate plates of the present form may 

 be due to its inmiaturity. This point can not be settled. That 

 robusttis is not the young of gotoi seems amply demonstrated by the 

 presence of a specimen of the latter having R 27 mm. The dif- 

 ferences hold good with the exception that in the small example 

 of gotoi the lower series of inferomarginal spines extends only half 

 the length of ray. Consequently in large specimens of rohustus it 

 may eventually be found that the lower inferomarginal series is much 

 more extensive. The absence of a second series of superomarginal 

 spines and of naked areas on the marginal plates will separate 

 rohustus from agassisi. The presence in agassizi of a well-marked 

 ventral face to the inferomarginals is also an important difference. 



