31 
U 
cludes that ,,we are therefore justified in assuming that in the 
Palæchinidæ there may have been in the young a similar radial 
system of five plates". It may be stated that 
the facts known of the anal plates in the Palæ- 
echinoidea do not support this suggestion any 
more than that of the presence of a primordial 
suranal plate. In Bothriocidaris the outer ring 
of anal plates is even decidedly interradial in Fi8- 1. Apical 
er > system of 
position, as shown in Fig. 1 (Comp. Jaekel:  Bothriocidaris. 
Uber die ålteste Echinidengattung Bothriocidaris. tk small outer plates 
Sitz. ber. Ges. naturf. Fr. Berlin. 1894. p. 245). nottheocular plates,as 
The Cidaroidea. The development of the eg okse BES 
apical system has been described by Dåderlein, før"? After Jaekel, 
A. Agassiz, Lovén and the present author. Dåderlein (Die 
Japanischen Seeigel. I. Cidaridæ u. Saleniidæ. 1887. Taf. V. 
Fig. 8, p. 28) describes and figures the apical system of a spe- 
cimen of (Goniocidaris biserialis of 3 mm diameter. ,,Genital-, 
Ocular- und Analplatten waren bereits gesondert; das Analfeld 
(nicht gråsser als eine Genitalplatte) war von sieben Platten be- 
deckt, die nach dem Verlauf der Nåhte deutlich 
darauf hinwiesen, dass eine einfache urspring- 
liche Analplatte erst in zwei, dann in drei Stiicke 
zerfallen war, deren jedes sich nun weiter theilte". 
(Fig. 2). It must certainly be agreed that this 
young stage does not prove that there was ori- 
Fig. 2. Apical 
system of a young 
Goniocidaris … up into several smaller ones, and the young stage 
biserialis (3 mm). (4 mm diameter) of Plococidaris (Leiocidaris) 
ginally a single anal plate, which later on broke 
Dåderiiii) verticillata, which Dåderlein figures (Op. cit. 
Taf. IX. Fig. 8) shows a quite similar arrange- 
ment and number of the anal plates, and thus cannot prove anything 
in this regard either. 
Å. Agassiz figures in the ,,Revision of Echbini" Pl. Il. c. 
fig. 8 the apical system of a young specimen of Dorocidaris 
