161 
To the description of the tuberculation should be added that 
the areoles of the primary tubercles in both ambulacra and inter- 
ambulacra are confluent on the oral side, generally unto the ambitus. 
A remarkable feature is observed on the tubercles, viz. a sort 
of fine crenulation, produced by a circle of dark coloured 
grains along the edge of the ring (or the „parapet of the platform“ 
in the Terminology of Bat her „Triassic 
Echinoderms of Bakonv“, 1909, p. 61). This 
may probably have nothing to do with ge¬ 
nuine crenulation, but, at any rate, it is 
well worth noticing. The same feature is to 
be observed in Notechinus magellanicus , but 
not in N. novæ-zealandiæ. 
Doderlein States that one Ocular is 
insert. The single specimen which he has 
examined must have been exceptional in 
this regard; in my material I find only very 
rarely Oc. I just touching the periproct; the 
rule is that all Oculars are exsert. As a rule there is only one 
primary tubercle at the inner edge of each genital plate, besides some 
secondary tubercles. The periproct is small (comp. measurements) 
and affords a very characteristic specific mark in the anal plate 
carrying one rather large tubercle; only very rarely it is lacking. 
Sometimes also a few of the other periproctal plates carry a tub¬ 
ercle (Fig. 9). 
Regarding the peristome Doderlein maintains that it is not 
quite naked, as stated by Loriol and myself. Here again the spec¬ 
imen studied by Doderlein must have been exceptional. It is a 
Fig. 9. Apical system of 
Pseudechinus albocinctus. 
3,8/1. 
rule that the peristome is quite naked, all my specimens are devoid 
of plates in the peristome, except of course the buccal plates. One 
specimen only presents the interesting abnormality that in one 
radius the buccal plates have been reduplicated, a pair of supple- 
mentary plates, each carrying a tubefoot, lying outside the primary 
pair, one of them close to the latter, the other nearer the edge of 
the peristome. Also the primary pair of buccal plates in this radius 
is slightly abnormal, the right plate being divided into two and de¬ 
void of a tubefoot. On this plate a sphæridia is found in the usual 
dense covering of ophicephalous and triphyllous pedicellariæ. 
Vidensk. Medd. fra Dansk naturh. Foren. Bd 73. 
11 
