xx THE VOYAGE OF H.M.S. CHALLENGER. 
On the basis of these researches Viguier proposed an amended classification of the 
Asteroidea. He divided the class into two sub-classes, named “ Astéries ambulacraires” 
and “ Astéries adambulacraires.” The first characterised by the predominance of the 
ambulacral plates in the mouth-ring, the presence of pedunculate forficiform or forcipiform 
pedicellarize, and the usually quadriserial arrangement of the ambulacral tube-feet ; the 
second sub-class characterised by the predominance of the adambulacral plates in the 
mouth-ring, by the presence of sessile, pincer-like, or valvulate pedicellarice, and by the 
almost constant biserial arrangement of the ambulacral tube-feet. The first sub-class was 
divided into three families, the “ Asteriadze,” Heliasteridze, and Brisingide. The second 
sub-class was divided into ‘seven families, the Echinasteride, ‘ Linckiade,” Goniasteride, 
Asterinide, Pterasteridee, Astropectinidee, and Archasteridee. 
The three families, Heliasteridee, Brisingidee, and Archasteridz are additions to those 
given in Perrier’s list. Perrier, however, included the family Brisingide in his remarks, 
but did not include it in his synoptical table. The genera recognised by Perrier are 
accepted by Viguier, Metrodira, Nepanthia, and Brisinga being the only additions on 
his list. Viguier, however, defined the genera chiefly on the basis of his own investiga- 
tions on the skeleton, the characters of the odontophore and the mouth-plates being used 
by him as important factors in the classification: On these grounds several of the genera 
are placed by Viguier in different families and associations from those to which they were 
referred by Perrier. 
In 1879 Zittel* published a classification having special reference to fossil forms. He 
divided the class Asteroidea into two orders—(1) the Ophiuride, which was again divided 
into two sub-orders, the Euryaleze and the Ophiure ; and (2) the Stelleridee, which was 
subdivided into two sub-orders, the Encrinasteriz and the Asteriz vere. The latter 
group—which comprises all the recent forms—was simply divided into two unnamed 
sections, characterised by the quadriserial and the biserial arrangement of the ambulacral 
tube-feet. 
In 1884 Perrier* again discussed the question of classification, and pointed out that the 
structure of the mouth determined by Viguier, and the character of the ambulacral furrow, 
are morphologically correlated, the one dependent on the other, and that the modifications 
in the form of the pedicellarize stand in no definite connection with the structure of the 
ambulacral furrow and the mouth. From this he was led to discuss the relative taxo- 
nomic values of the structure of the ambulacral furrow and mouth on the one hand, and 
of the form of the pedicellariz on the other. He decided in favour of the pedicel- 
larize, on the ground that they are in his opinion aborted rudiments of ancestral organs 
1 Handbuch der Paleontologie, Miinchen, 1879, Band i. p. 437. 
2 Mémoire sur les Etoiles de mer recueillies dans la mer des Antilles et le Golfe de Mexique durant les 
expéditions de dragage faites sous la direction de M. Alexandre Agassiz (Nouv. Archives Mus. Hist, Nat., 
2e Série, t. vi, (1884) p. 134). 
