STARFISHES OF THE PHILIPPINE SEAS. 405 



Superambulacral plates present. These are attached to the lower 

 end of the ambulacral ossicles and the upper end is subtruncate and 

 often broader than the lower, which is more or less rounded. 



Tyfe,—Q2X. No. 32642, U.S.N.M. 



Type-locality. — Station 5543, oft' Point Tagolo, northern Minda- 

 nao, 162 fathoms, sand; bottom temperature, 54.5° F. 



Distribution. — Known only from the type-locality. 



Family METRODIRIDAE Fisher. 



Metrodirinae Sladen, 1889, p. 415. 

 Metrodiridae Fishee, 1917d, p, 171. 

 Diagnosis. — Whole skeleton overlaid by a rather thin skin par- 

 tially obscuring the outlines of the plates; rays slender; abactinal 

 plates tessellate, partly imbricated, with small spines; marginal 

 plates large, forming side wall of ray, there being 1 or more series 

 of intermarginal plates on the proximal part of ray; actinal inter- 

 mediate plates reduced to one, between mouth plates and infero- 

 marginals; papulae isolated, strictly abactinal; tube feet with suck- 

 ing disk devoid of calcareous deposits; ampullae single; interbra- 

 chial septa rudimentary, practically absent. 



Genus METRODIRA Gray. 



Metrodira Gray, 1840, p. 282. Type, Metrodira subulata Gray. 

 Scaphaster de Loriol, 1899, p. 27, pi. 3, fig. 1. Type, Scaphaster humherti 

 DE Loriol. 



This puzzling genus was placed in the Linckiidae by Sladen (1889, 

 p. 415), and other authors have followed his lead. 



It shows an outward resemblance to the Asteropidae, however, 

 barring the single fact of the very slender rays. De Loriol (1899, 

 p. 27) described a very young example as a new genus which he 

 placed in the Gymnasteridae (= Asteropidae) near Asteropsis 

 {=Petricia) . 



Sladen stated that " its external facies and general structure ap- 

 pear to indicate an intermediate position between the Linckiidae 

 and Echinasteridae." 



Unfortunately the specimens at my disposal are small. The char- 

 acters which would lead one to place this genus in the Asteropidae 

 (restricted to Asterope and Petrkia) are as follows: 



The thin skin which covers the plates and spines; the conspicuous 

 marginals not unlike those of Petricia; the loosely tessellate abac- 

 tinal skeleton, bearing skin-covered spinelets. The characters which 

 are adverse, so to speak, are : The conspicuous series of intermarginal 

 plates, the absence of actinal intermediate plates, except a single 

 plate back of the mouth plates; the rudimentary interbrachial sep- 

 tum without a calcareous pillar (perhaps, however, due to small size 

 of disk) ; the single ampulla to each tube foot. 

 13434— Bull. 100—19 27 



