ah 
REPORT ON THE CRINOIDEA. . 399 
V'avons etabli, des plaques dorsales disposées au début, comme celles du calice des 
Crinoides ; nous avons démontré que, chez les Brisinga, les plaques de la premiere rangée 
deviennent les odontophores.” Even yet, however, no figures of the various develop- 
mental stages of Brisinga have been published in “ demonstration” of Perrier’s 
statements, which were summarised as follows, “ Aisi les odontophores sont les restes 
des pitces du premier rang du disque primitif de la Brisinga. Lidentité évidente du 
plan dorganisation des Brisinga et des Astéries proprement dites rend la méme conclu- 
sion probable pour les autres Etoiles de mer.” It is undoubtedly probable that what is 
true of Brisinga also applies to all the other Asterids ; and it is therefore the more 
desirable that some proof should be offered of the very definite statements made by 
Perrier. They have recently been disputed by Sladen! on the ground that in all the 
Starfishes of which the embryonic stages are sufliciently known, the basals and odonto- 
phores are “ separate and distinct, and co-exist independently from their first formation ;” 
while he further expresses his belief, based on sound morphological argumeuts, that the 
origin assigned by Perrier to the odontophores of an Asterid is theoretically impossible. 
Perrier has recently repeated his statements in somewhat greater detail,’ and having 
compared Lovén’s figures of the young Asterias glacialis with his young specimens of 
Brisinga, he says that he has no doubt whatever, “que les choses se passent de la méme 
facon dans les deux genres, et nous pouvons, dés lors, affirmer que les piéces radiales (sic) 
des tres jeunes Asteriadze deviennent dans cette ordre de Stellérides les odontophores.” 
Unfortunately for his theory, however, these interradial abactinal plates of the 
young Asterias develop in other Starfishes into relatively large plates which remain in 
more or less close relation with the dorsocentral, and are the very plates described as 
basals by Sladen not only in the larval Asterias, but also in the following genera 
Zorouster,? Pentagonaster, Tosia, Astrogonium, Stellaster, Nectria, Ferdina, Pentaceros, 
Gymnasteria, and others. 
As there is an odontophore on the ventral side in each of these types, it is perfectly 
1 Quart. Journ. Mier. Sci., 1884, vol. xxiv., N. S., p. 39. 
2 Mémoire sur les Etoiles de Mer recueillies dans la mer des Antilles et le Golfe du Mexique durant les expéditions 
de dragage faites sous la direction de M. Alexandre Agassiz, Nouv. Archiv. du Mus. @ Hist: Nat., 2™° sér., 1884, t. vi. p. 159. 
3 Several months before the appearance of Perrier’s Report upon the West Indian Starfishes, Sladen figured the 
apical system of Zoroaster fulgens, and described it in the following terms: “Surrounding a dorsocentral and five small 
radially placed plates are five large plates interradial in position ; and outside and alternating with these are five 
similar but rather smaller radially placed plates. . . . It will be noted that these plates represent in a remarkable manner 
the dorsocentral, the under-basals, the basals, and the radials respectively of the Crinoid calyx” (Asteroidea dredged in 
the Farée Channel during the cruise of H.M.S. “Triton” in August 1882, Trans. Roy. Soc. Edin., vol. Xxxii. p. 160, 
figs. 9,11). Precisely the same arrangement appears in the apical system of Zoroaster ackleyi, so far as one can judge 
from Perrier’s figure of an entire specimen (Nouv. Archiv. du Mus. @ Hist. Nat., 2™° sér., 1884, t. vi. pl. iti. fig. 1)5 but he 
makes no mention of Zoroaster fulgens. Even if he had not seen Sladen’s reference to it, one would have thought that 
he would have been struck by the Crinoidal aspect of Zoroaster ackley?, though he does not refer to it at all, and he 
gives no detailed description of the plates. It would be interesting to know his reasons for believing that the large 
interradial plates in the immediate neighbourhood of the dorsocentral are not the “plaques de la premitre rangée” 
of the larva, which occupy exactly the same position with reference to the dorsocentral, and are believed by Perrier 
to become the odontophores in all Starfishes except Caulaster. 
