31 
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 
position, as shown in Fig. 1 (Comp. Jaekel: 
system of 
Bothriocidaris. 
tiber die alteste Echinidengattung Bothriocidaris. (The small outer plate* 
represent the genital 
Sitz. ber. Ges. naturf. Fr. Berlin. 1894. p. 245). nottheocniarpiates,as 
The Cidaroidea. The development of the lo conclu(ie from the 
apical system has been described by Doderlein, After Jaekel - 
A. Agassiz, Lovén and the present author. DOderlein (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 grosser als eine Genitalplatte) war von sieben Platten be- 
deckt, die nach dem Verlauf der Nahte deutlich 
darauf hinwiesen, dass eine einfache urspriing- 
liche Analplatte erst in zwei, dann in drei Stucke 
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¬ 
ginally a single anal plate, which later on broke 
up into several smaller ones, and the young stage 
biserialis (o mm). (4 mm diameter) of Plococidaris (Leiocidaris) 
(After 
Do der le in) verticillata , which Doderlein 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. 
A. Agassiz figures in the „Revision of Echini“ PI. II. c. 
fig. 8 the apical system of a young specimen of Dorocidaris 
Fig. 2. Apical 
system of a young 
Goniocidaris 
