CLASSIFICATION, 
CONTENTS. 
J. Hisrory oF THE CLASSIFICATION OF THE ASTEROIDEA. 
‘TIL REASONS FOR CONSIDERING PREVIOUS CLASSIFICATIONS INVALID. 
TII. A CLASSIFICATION OF THE ASTEROIDEA BASED ON Factors OF MORPHOLOGICAL IMPORTANCE. 
I. History of the Classification of the Asteroidea. 
The earliest attempt to classify the Asteroidea was made by Linck’ in 1733, who 
published the first monograph devoted to starfishes, entitled: De Stellis marinis liber 
singularis. It is a work worthy of honour, and one which I hold in reverential estima- 
tion. Linck divided the “ Stelle marine” into two sections, named “ Stelle fisse” and 
« Stelle integre ”—the former characterised by the presence of an open channel or ambu- 
lacral furrow along the actinal surface of each of the lobes or rays of the body, the latter by 
the absence of these open channels. The Stellx fissw correspond to the Asteroidea of the 
present nomenclature; the Stella integrx comprise the Ophiuroidea and the Comatulee. 
Linck divided the Stellz fisse, or section equivalent to the Asteroidea, into three classes, 
which were based on the number of the rays; the first class embraced forms with less 
than five rays (all, by the way, abnormal or monstrous forms), the second forms with five 
rays, and the third all those with more than five rays. The classes were subdivided into 
genera, those included in the first and third being distinguished by the number of their 
rays. = In the second class, however, the gentra were characterised by the general form. 
This class contained seven genera, four of which are still maintained, viz., Pentagonaster, 
Pentaceros, Astropecten, and Palmipes. 
It will be seen from the above that the basis of Linck’s classification is purely artificial, 
the number of rays being the determinating factor. 
In 1766 Linné,? in the 12th edition of his Systema Nature, grouped all the 
Asteroidea, Ophiuroidea, and Comatulee known to him in one genus, Asterias, which he 
1 De Stellis marinis liber singularis, Lipsie, 1733. 
2 Systema Nature, Editio Duodecima, Reformata, Holmiz, 1766. 
GS 
(Z0OL. CHALL, EXP.—PART LI.—1888.) 
