242 Bulletin Vanderbilt Marine Museum, Vol. VI 



coloration to become uniform and somewhat lighter. Those re- 

 maining concealed tend to retain their purplish coloration, while 

 those that change their habitat to exposed locations on the reefs 

 and flats tend to become a uniform yellow-brown. 



Technical description : Stellate, rays slender, tapered dis- 

 tally, tips rounded ; rays variable in number, due to autotomus di- 

 vision, normally 5 or 6, less frequently 4 to 9. 



R==150 mm. ; r= 20 mm. Abactinal surface with the plates 

 small, numerous, closely set, with their edges frequently over- 

 lapping, usually with no connective ossicles, except small, lateral 

 ones ; plates irregularly polygonal, thick, moderately convex dor- 

 sally and externally densely covered with fine, close-set granules. 



The papular areas are large, in series of 8 to 12 or more, with 

 the median ones very irregular, obscure ; the papulae small, nu- 

 merous, 10 to 42 ; the pores are normally much smaller than the 

 larger granules of adjacent plates. The marginal plates are 

 arranged in two nearly equal rows and are larger and more 

 quadrangular in shape than the abactinal plates. The interactinal 

 plates are arranged in two long, regular rows and some shorter, 

 smaller, squarish plates. The interradial plates are small, ar- 

 ranged in triangular groups; these are covered and practically 

 concealed by crowded, fine granules, similar to those on the abacti- 

 nal plates. The adambulacral plates bear two rows of small, short 

 spines and proximally on the adjacent series of interambulacral 

 plates there is a third row of similar small spines, parallel to the out- 

 er row. These interactinal spines are of the same number and placed 

 opposite to the outer series of interambulacral spines. The granu- 

 lation of the actinal surface, which is like that of the abactinal 

 surface, does not extend up into the ambulacral grooves ; the fur- 

 row spines are adjacent to one another and are not separated by 

 granules. (See pi. 73, fig. B.) 



The single specimen, taken by the "Alva" at Venus Point 

 Reef, Tahiti, is identical in structure with those from the West 

 Indies and lower Caribbean examined by the writer. 



References: Linckia guildingii. Gray, J. E., Ann. Mag. Nat. 

 Hist, ser. 1, vol. VI, 1840, p. 285. — Agassiz, A., Mem. Mus. 

 Comp. Zool., vol. V, 1877, p. 105, pi. XIV, figs. 1-6.— Fisher, 

 W. K., Bull. 100, vol. Ill, U. S. Nat. Mus., 1919, p. 401.— 

 Clark, H. L., Papers Dept. Marine Biol., Carnegie Inst., 

 Washington, Publ. 214, 1921, p. 67. 



