XVlil THE VOYAGE OF H.M.S. CHALLENGER. 
divided into three sections, named Integra, Stellatx, and Radiate. The representative 
of the first of these sections cannot now be recognised ; the second section is equivalent 
to the Asteroidea, and comprised nine species; the third section embraced the Ophiuroidea 
and Comatulee. 
Lamarck,’ in 1816, divided the Asterias of Linné (which he regarded as a family 
under the name of ‘‘ Les Stellerides”) into four genera, which he named Comatula, 
Euryale, Ophiura, and Asterias, the last being equivalent to the section “ Stellatx” of 
Linné, and to the Asteroidea of the present day. He divided the genus Asterias into two 
sections: (i.) ‘Asteries scutellées,” and (ii.) ‘ Asteries rayonnées,” the former embracing 
the species in which the length of the ray does not exceed that of the diameter of the disk, 
and the latter those in which the length of the ray is greater than the diameter of the disk. 
In 1830 de Blainville* proposed to divide the Asteroidea (which he ranked as a family, 
“ Asteridea ”) into five sections (“ genres ou sous-genres ”), which were characterised by 
the general form, and by the number of the rays. The composition of the different 
groups was more or less heterogeneous, and none of them have been maintained. 
In 1834 Nardo® grouped a number of species known to him into five genera, two of 
which are maintained, viz., Asterina and Linckia. 
In 1835 Agassiz* divided the Asterias of Lamarck (which he ranked as a family in 
the order “ Les Stellerides”) into nine genera, including fossil forms. Of the eight genera 
in which recent forms were included, two are maintained i statu quo (Ophidiaster and 
Culcita), and the name of a third (Gonzaster) is used in a restricted sense. The remaining 
genera correspond to groups named by Linck or Nardo. 
This partition of genera was based on a number of structural characters, and was the 
first approach towards a morphological classification of the group. 
In April 1840 Miiller and Troschel’ published a preliminary classification of the 
Asteroidea, which they divided into three unnamed families, characterised by the presence 
or absence of an anal aperture, and by the quadriserial or biserial arrangement of the ambu- 
lacral tube-feet. Fourteen genera were defined by means of structural characters, and 
representative species were cited. ‘Two years later this work was expanded into a com- 
plete monograph on the group, entitled: System der Asteriden (Braunschweig, 1842), 
which has formed the basis of all subsequent systematic work on the Asteroidea. In the 
monograph the three families above indicated comprised eighteen genera, which included 
140 species. 
1 Hist. Nat. Anim. s. vert, t. ii. p. 530, 1816. 
* Dict. Sci. Nat., art. “ Zoophyte,” t. Ix. p. 216, 1830; Manuel d’Actinologie ou de Zoophytologie, 1834, 
p. 235. 
8 De Asteriis, Oken’s Isis, 1834, Heft vii. p. 716. 
4 Prodrome d’une Monographie des Radiaires ou Echinodermes, Mém. Soc. Sci. Nat. Neuchatel, t. i. 1835, 
p. 190. 
5 Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, April 1840, p. 102. 
