ii6 DISCOVERY REPORTS 



Genus Asterodon Perrier 



Asterodon Perrier, Comptes rendus, cvi, 1888, p. 765. — 1891, p. 129. Type A. singularis (Miiller & 

 Troschel). — Verrill, 1899, p. 203. 



Asterodon singularis (Miiller & Troschel) 



Goniodisciis singularis Miiller & Troschel, Arch, fiir Natiirgescli., ix, 1843, p. 116. 



Asterodon granulosus Perrier, 1891, p. 132, pi. 11, figs. 4a, 46. 



Asterodon singularis Perrier, 1891, p. 134, pi. 13, figs. 3a, 36. — Ludwig, 1903, p. 19. — 1905, p. 40, 



pi. 5, figs. 1-3. — Koehler, 1923, p. 84. 

 Odontaster singularis Bell, Proc. Zool. Soc. Lond., 1893, p. 262. — Leipoldt, 1895, p. 614 (list of 



references). — Meissner, 1896, p. 92, pi. 6, figs. 5, 5 a (type), 6. — 1904, p. 19. — Clark, 1910, 



p. 332, pi. 2, fig. 4. 



St. WS 583. 53° 39' S, 70° 54^' W (Strait of Magellan), 14-78 m., i specimen, forma granulosus. 



It is evident that there are two intergrading formae, paralleling those found in 

 Odontaster penicillatus and Acodontaster elongatiis gramdiferus. 



Forma singularis. 



Form stellate, with well-developed rays. Marginal plates more numerous (upward of 

 18), not encroaching widely upon the abactinal and actinal surfaces. Granuliform 

 pedicellariae present or absent. 



Miiller and Troschel's type has been figured by Meissner, 1896, pi. 6, figs. 5, 5(7. 

 Other figures are Perrier, 1891, pi. 13, figs. 3^, 36; Ludwig, 1905, pi. 5, fig. i ; Leipoldt, 

 1895. pl- 31. fig- la-c; Clark 1910, pi. 2, fig. 4. 



Forma granulosus. 



Asterodon granulosus Perrier, 1891, p. 132, pi. 11, figs. 4a, 46 (Punta Arenas). 



Form arcuately pentagonal, with short rays, marginals of both series fewer (upward 

 of 12) and heavier, forming a broad margin to body. Pedicellariae present. 



Both the specimen figured by Perrier and that by Ludwig (1905, pi. 5, figs. 2, 3) are 

 young. The specimen from St. WS 583 has R 35-5 mm., r 21 -5 mm. It is notable for the 

 broad marginals, 12 to a ray (in addition to interradial marginal). The first 2-5 adam- 

 bulacral plates have 2 furrow spines, the rest i. The abactinal, marginal, and actinal 

 plates carry (in the aggregate) numerous pedicellariae with 2-4 granuliform valves which 

 do not rise above the general surface of the granules. 



If this specimen is compared with the published figures of singularis, the supero- 

 marginals appear to be at least twice as broad, while the ray is broader, shorter, and more 

 obtuse. 



Type locality. Chile. Type no. 754, Berlin Museum, yz^/e Meissner, 1896. 



Distribution. Coasts of Tierra del Fuego, north along the west coast of South 

 America to 20° S latitude ; low tide to 80 m. 



