33 
it is not so. In the „Panamic Deep Sea Echini u (p. 4, fig. 15) 
A. Agassiz gives a detailed figure of the anal area of a spe- 
cimen 1,5 min in diameter, showing „that in the youngest stages, 
about the size of that examined by Lovén, there are already five 
anal plates“; as shown by the figure (PI. 13, fig. 6) there are 
three outer, larger plates and two quite small ones inside these. 
1 have myself examined a specimen in exactly the same stage as 
that figured by L o v é n in the quoted Fig. 6, PI. II, and can say 
that the apparent large central disk is not really a single plate; 
I found there three distinet plates, slightly overlapping with their 
edges so that it could only be ascertained by a very careful 
examination that it was not a single plate. 
In „Die Echinoiden der deutschen Siidpolar - Expedition“ x ) I 
have figured (Taf. XI, Pig. 4) a young stage of Bhynchocidaris 
triplopora showing the first development of the anal plates. It 
shows a single small plate lying in the space left between the 
five large genital plates; in another specimen two other small 
plates had just appeared in the anal area. Evidently we have 
then here the same mode of development of the anal plates as 
in Austrocidaris canaticulata, several small plates appearing almost 
contemporaneously. Certainly one of these plates appears in Bhyn¬ 
chocidaris, , a short time before the others; but it seems to be quite 
uujustified to lav so mueh stress on this faet as to claim on that 
ground alone the homology of this small plate with the central 
plate of Salenids — or even with the dorso-central plate of Crinoids. 
It is then not quite correct in the description of this developmental 
stage, that I have noticed the first formed plate as „die Anal¬ 
platte “ (Op. cit. p. 11). 
In the work quoted I have described a young stage of 2 mm 
diameter of another viviparous Cidarid, Notocidaris gaussensis (p. 
21). It is stated „dass ich am Analfeld nur eine Platte unter- 
scheiden kann“. As this statement seems contradictory to the 
b Deutsche Siidpolar-Expedition. XI. Zoologie III. 1909. 
Vidensk. Meddel, fra den naturh. Foren. 1911. Bd. 63. 
