DESCRIPTION OF SPECIES. 



Family PORCELLANASTERIDAE Sladen, restricted.^ 



Genus SIDONASTER Koehler. 



Sidonaster Koehleb, 1909, p. 37. — Fisher, 1911(?, p. 23. 



SroONASTER VANEYI Koehler. 



Plate 3, fig. 3. 

 Sidonaster vancyi Koehler, 1909, p. 37, pi. 3, fig. 6 ; pi. 6, fig. 5 ; pi. 10, fig. 3. 



Diagnosis. — R=:36 mm.; r=15 mm.; R = 2.4 r (Koehler's type 

 R = 2 r). Abactinal integimient of disk covered with small spine- 

 lets as far as distal edge of cribriform organ, that of rays being bare; 

 superomarginals 5 to 7 with one upright spine and 1 or 2 smaller 

 accessories; terminal plate with 7 spines; adambiilacral spinules 1 

 or 2, usually 2, the plates strongly hollowed on furrow margin; 

 mouth plates with a median unpaired spinule, and spaced from this 

 2, 3, or rarely 4 marginal spinules at mouth of furrow. 



Notes on Philippine specimens. — The 4 specimens combine cer- 

 tain characters of S. vaneyi and S. hatheri. It has in fact been 

 difficult to decide what to name them. The two specimens from sta- 

 tion 5215 are much larger than Koehler's specimens of either vaneyi 

 or hatheri, since the type of vaneyi has R = 20 mm., and that of 

 hatheri not more than 26 mm. Koehler has so carefully described 

 both species that I shall need only to point out the diiferences pre- 

 sented by the Philippine examples. 



The abactinal spinelets do not extend quite so far distally on the 

 radii as figured by Koehler. Two large specimens from station 5215 

 vary in this respect, one being about intermediate between the condi- 

 tion of typical vaneyi and hatheri. Along the edges of the abactinal 

 integument the spinelets extend to the distal edge of the cribriform 

 organ, but on the radial line little if any farther than an intersecting 

 line drawn between the middle of two adjacent cribriform organs. 

 Thus the spinous and papular area is deeply concave radially, and 

 the varying amount of this concavity (even on different radii of the 

 same specimen) controls the width of the interradial band of abac- 

 tinal spinelets. Abactinal spinelets are as described by Koehler, 

 and 1.5 mm. long. 



1 As noted under the Goniopectinldae, the Ctenodisclnae are more properly referable to 

 that family. Fisher, 1916a, p. 1. 



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