240 



THE STELLEROIDEA 



the systematic study of the Stelleroids, included members of both 

 sub-classes in his group "Stella." He separated the Asteroids as the 

 Stellae fissae, which he divided according to the number of arms or 

 rays into such divisions as Trisactis, Tetractis, Hexadis, etc. Linnaeus 

 in 1766 included both sub-classes as well as some unstalked 

 Crinoids in his genus Asterias, grouping all the starfish together as 

 "Stellatae." Lamarck in 1816 (21), de Blainville (1830 and 

 1834), Nardo and Brandt (1834), and L. Agassiz (1835) proposed 

 various divisions of Asterias, which these authors recognised to be 

 a family or order. In 1840 Gray's Synopsis, and Miiller and 

 Troschel's essay, Ueber die Gattunyen der Asteiien (35), first prepared 

 the way for a scientific classification. In 1842 the latter authors' 

 System der Asteriden (36) laid the foundation for all later work. 



After that date additions to our knowledge of the recent Asteroids 

 have been made by many authors, especially A. Agassiz, Barrett, 

 Bell, Danielssen, Fewkes, Forbes, Gray, Jullien, Koren, de Loriol 

 le Fort, Liitken, Marenzeller, Martens, Moebius, Perrier, Philippi, 

 Sars, Sladen, E. A. Smith, Stimpson, Studer, Thompson, Verrill, 

 Viguier. The fossil forms have been described by E. Billings, Eck, 

 Forbes, E. Fraas, Goldfuss, Heller, Hall, de Loriol le Fort, Miiller, 

 C. F. Roemer, Salter, Simonowitsch, Stiirtz, Wright, and others. 



The study of the anatomy of Asteroids received its first stimulus 

 from the researches of Joh. Miiller (34). The skeleton has been 

 described by Meckel (1828), Duvernoy (1848), Gaudry (13), and 

 especially Viguier (52). Perrier has devoted most attention to the 

 pedicellariae (1875 and 1884). The study of the visceral anatomy 

 was begun by Tiedemann, Delle Chiaje, and Meckel ; and of the 



nervous system by Krohn. 

 The present position of the 

 subject is due mainly to 

 Ludwig (25), Cuenot (8, 9), 

 and Hamann (17). 



The embryology has 

 been worked out by many 

 authors, the study of the 

 early stages being unusually 

 easy ; among contributions 

 to this branch of the subject 

 are those of Joh. Miiller 

 (1848 - 55), A. Agassiz 

 (1877), Ludwig (1882), 

 MacBride(1893 and 1894), 

 (32, 33), and Bury (1889 

 and 1895). 



The principal classifications after those of Gray, and of Miiller 

 and Troschel, are those of Viguier (1878), (52), based on the oral 



Fio. 



Actinal surface of Asterias ri<l>ens with a podion (o) 

 enlarged. 



