92 TH. MORTENSEN, (Schvved. Südpolar- Exp. 
answers, upon the whole, very well to the careful and accurate description given by 
Koehler; but, since Professor KOEHLER had likewise only a single specimen at 
his disposal, it is not surprising that I have some additional information to give. 
In PI. XI Figs. 1 7, 19 are given photographic representations of the specimen, which 
seem to me not superfluous, especially in view of the several minor differences from 
the type, as figured by KOEHLER. 
The shape of the test is as in the type specimen, excepting that it is somewhat 
lower (length 48 mm., breadth 43 mm., height 29 mm.). The vertex is central. The 
apical system differs rather much from that of the type specimen, as figured by 
KOEHLER (Op. cit. PL VI Fig. 43). Only three genital pores are developed, the right 
anterior one is wanting, while it is developed in the type specimen. In the figure quoted 
the madreporic plate is represented as being separated from the right anterior genital 
the text nothing is said of this very unusual feature, 
which — as it cannot be supposed to be an error in 
the figure, it being expressly stated that the plates of 
the apical system are very distinct — I would sug- 
gest to be an abnormality. In any case the present 
specimen shows the usual condition, the madreporic 
plate being the posterior prolongation of the right 
anterior genital plate (Fig. 24). — The fact that such 
a case is also met with in Amphipn. Koehleri (comp, 
below, p. 98 Fig. 28) should be mentioned on this 
occasion; there it is evidently an abnormality. 
The ambulacra correspond to those of the type 
specimen, the number of the plates only being slightly 
smaller, in accordance with the smaller size of the specimen. Regarding the inter- 
ambulacra it should be noticed that the plates are not elevated in the middle, as is 
the case in the type specimen. In the structure of the actinal plastron I find some 
noteworthy differences from what is seen in the type specimen, as represented by 
Koehler (Op. cit. PI. V Fig. 37). The labrum is there shown to reach the fourth 
ambulacral plate, and the sternum is undivided, the plastron thus being merido- 
sternous. In the specimen before me the labrum ends off the third ambulacral plate, 
and only the second ambulacral plate is quite short (Fig. 25), while in the type spe- 
cimen the 3 — 4 inner ambulacral plates are represented as being quite short. The 
sternum consists of two plates, after the usual amphisternous type (Fig. 25); the suture 
between these two plates is, however, difficult to trace, and can only be seen with 
certainty after treating the specimen with alcohol-glycerin. I cannot doubt that this 
suture is really present also in the type specimen; a variation from the amphisternous 
to the meridosternous type, even in one and the same species, is, I think, impossible. 
plate by a transverse line; in 
Fig. 24. Apical system of Amphi- 
pneustes Lorioli; the tubercles are 
omitted. 8 /i. 
