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ASTROPHYTON. 



Ophiomyxa pentagoua Mull. & Trosch. 



OpMura penlagona Lamk. An. s. Vert., II. p. 546. 



Ophiomyxa pentagona Mull. & Trosch. Syst. Asterid., p. 108. 



LIST OF SPECIMENS. 



■Whence obtained. 



Museum of Comparative Zooloyy. 



Jardin des Plantes. I Alcoholic. 



ASTROPHYTON Linck. 



Type of the Genus, A. arborescens.* 



Disk and arms covered with thiclc skin, without scales. Radial 

 shields extending nearly or quite to the centre of the disk, and form- 

 ing more or less elevated radial ribs. Two short genital slits in each 

 interbi'achial space, lying close to the margin of the disk. Teeth, 

 tooth-papilliB, and mouth-papilla3 all similar and spiniform. Arms 

 forked many times. No arm-spines, except at the tips of the branches, 

 where they have the form of microscopic hooks. Tentacle-scales. Un- 

 der and side arm-plates very small, and buried beneath the skin of the 

 under side of the arm. 



SPECIES HEREIN DESCRIBED. 



Disk entirely granulate above ; grains flat ; ribs low, 

 Disk entirely granulate above ; ribs distinct, 



Only ribs closely granulate, 



Ribs with a few short, irregular spines. 

 Disk above closely beset with thorny stumps, 

 Disk closely beset above with little thorny spines, 

 High ribs bearing a few clavate stumps. 



A. arborescens. 

 A. Lamarckii. 

 A. eucnemis. 

 . A. Caryi. 

 A. Agassizii. 

 A. Linckii. 

 A. clavatum. 

 A. costosum. 



* As the specific identification of Linck's plates cannot now 

 described species, Stella Arborescens Rond., as the generic type. 



be made, I have taken the oldest 



