159 
N. magellanicus, given in my report on the Echinoidea of the Swed- 
ish South Polar Expedition, p. 37). Also the tuberculation is rather 
different in the two species, especially the primary ambulacral 
tubercles are much less confluent in N. magellanicus than in the pre¬ 
sent species. Finally the large globiferous pedicellariæ are conspic- 
uously different in the two species. 
The Var. novæ-amsterdamiæ Doderlein of N. magellanicus would 
appear to stand nearer to the New Zealand species than to the typ- 
ical form of N. magellanicus, this variety being distinguished by its 
greater number of ambulacral plates and the smaller size of its 
apical system. Doderlein (Echinoideen d. Deutschen Tiefsee-Ex- 
pedition p. 230) gives for a specimen of 22 mm h. d. 18 inter- 
ambulacral and 26 ambulacral plates. In a specimen of 25 mm h.d. 
which I have received from Prof. Doderlein, I find 22 ambul¬ 
acral and 16 interambulacral plates; the apical system is only 5 
mm in diameter. It is evident that in these regards this variety is 
more in conformity with the New Zealand species than with the 
typical N. magellanicus. But then the colour of the test is distinctly 
reddish as in magellanicus, although lighter, as stated by Doder¬ 
lein, and the globiferous pedicellariæ are notably slenderer than 
in the New Zealand species. The var. novæ-amsterdamiæ thus oc- 
cupies an intermediate position between the two species, but is 
distinctly different from both. I should, indeed, be more inclined to 
regard it as a separate species. 
The discovery of a new species of this hitherto monotypic ge¬ 
nus is of considerable interest from a classificatory point of view, 
giving additional proof that Doderlein was perfectly right in 
establishing a separate genus for the species magellanicus ; the oc- 
currence of two kinds of globiferous pedicellariæ in this genus is 
especially interesting; the faet that both species agree in this feat¬ 
ure shows that it is a character of real value. Also from a zoo- 
geographical point of view it is of considerable interest to find 
this genus represented by related species in the New Zealand and 
the South American seas. 
