38 
suboral spines (one on eack side) are three-edged and liollowed on 
tke sides (Fig. 1), as in Pt. trigonodon Fisher. Actinolateral mem- 
brane only slightly developed. Pseudopaxillæ with low 
stalk, carrying 3 long, siender spines. Those round 
the anal opening larger. The supradorsal membrane 
is thin, withont distinet reticulation; no spicules. 
Spiracula few, singly placed. Papulæ simple. The 
madreporite is knob-shaped, close to the anal opening. 
Tubefeet in two rows. Disk only slightly arched. 
In general appearance it resembles Pt militaris, 
from which it is, however, very well distinguished, 
as it is, indeed, from all species of this genus hitherto 
described. — Though found in a Greenland fjord, it is 
evidently no arctic species, but belongs to the fauna 
of the warm area of the Northern Atlantic, as ap- 
pears from the faet that it was found together with 
such forms as Lætmogone violacea, Amphiura denti- 
culata a. o. — That it will prove to have a similar 
wide distribution as these forms can scarcely be 
doubted. 
2. Ophiozona tjalfiana n. sp. 
One specimen taken at 64° 05' N. 55° 20' W, 1100 M. by the 
“Tjalfe”-Expedition ( 8 /s 1909). 
Diameter of disk 6 mm, length of arms ca. 15 mm. Disk flat, 
covered with comparatively large scales, among which the central 
plate and a circle of 7 scales surrounding it are especially con- 
spieuous. Radial shields comparatively small, with their outer ends 
in contact or just separated by some small scales. Some small 
irregular scales separate the first dorsal arm-plate from the radial 
shields. The proximal dorsal arm plates are broadly in contact; 
from the 6th they are separated, the distance becoming gradually 
larger farther out on the arm; they are trianguiar, with the outer 
side rounded and tbickened, accordingly somewhat prominent, as 
seen in side view. 
■ 
i 
Fig. 1. Suboral 
spine of Ptera- 
ster hastatus. 
2r >/i. 
