Boone, Echinodermata r Cruises of "Eagle" and "Ara," 1921-28 79 



Luidia Columbia H. L. Clark, Bull. Mus. Comp. Zool., vol. 52, p. 331, 

 pi. 1, fig. 2, October, 1910. 



Suborder: Valvata. 



Family: OPHIDIASTERIDAE. 



Genus : LINCKLA. Nardo. 

 Linckia columbiae Gray. 



Plates 39 and 40. 



Type: Gray's type was collected in the Bay of Caracas, West 

 Colombia, on the rocks at low water, by H. Cuming, and is deposited 

 in the British Museum. 



Distribution : A littoral species known from Lower California to 

 northern Peru, including the Galapagos Islands. 



Material examined : One specimen, collected in Webb Cove, Albe- 

 marle Island, Galapagos Islands, February 3, 1928. 



Color : In life the abactinal surface is cocoa-brown with numerous 

 smaller brown flecks. This coloration persists on the outer portion of 

 the actinal surface also, the median portion of the disk and rays being 

 dirty light cocoa or cream color. 



Technical description: The single specimen taken by the "Ara," 

 presents a curious malformation due to the regeneration of three of 

 the five arms. The fully developed arm has an R of 104 mm., 

 r = 19 mm. The normal rays are long, slender, tapered, well rounded. 

 Only five-rayed specimens have been recorded, among the few speci- 

 mens taken, but L. columbiae evidently possesses the capacity to 

 regenerate lost arms in about the same degree as L. guildingi. It is 

 probable that specimens of L. columbiae with four to seven arms 

 may be found. The abactinal plates in this species are numerous, 

 thick, irregularly polygonal, a little convex with the margins occa- 

 sionally overlapping. The dorsal surface of the plates is regularly 

 paved with large, rounded granules which are also found between the 

 apertures of the papular areas, which latter are conspicuous and large 

 with numerous papulae. The supero- and inferomarginal plates are 

 nearly equal in size, each being irregularly polygonal or suboval and 

 somewhat larger than those of the abactinal surface. The interactinal 

 plates are small, crowded, and are covered by the crowded granula- 

 tion. The adambulacral plates bear a single row of stout, thick, sub- 

 cylindrical, blunt-tipped spines, set close together well down in the 

 furrow margin. On the outer margin of the adambulacral plates there 



