THE ECHINOIDEA. 
Bd VI: 4) 
87 
pedicellariæ occur. — Otherwise I have nothing to add to the description given by 
AGASSIZ (Op. cit., under the name of Hemiaster australis and cavernosus). 
The pedicellariæ do not afford very useful characters. Globiferous pedicellariæ 
I have not found, except in a fragment from South Georgia labelled H. Agassizii 
by Prof. Pfeffer; its somewhat deepened frontal ambulacrum and shorter posterior 
petals, however, make it very probable that it is not this species but cavernosus ; 
the globiferous pedicellariæ end in two teeth, which would seem to show that it be- 
longs to the var. bidens. (The posterior end of the test is not preserved so that it 
could not be seen whether the subanal tubefeet have been developed or not.) In 
case the H. elongatus is really a synonym of this species, the globiferous pedicella- 
riæ are provided with two teeth as in cavernosus var. bidens. The rostrate pedi- 
cellariæ are of the usual form; the tridentate pedicellariæ, on the other hand, differ 
from those of the other species in having, viz. the larger ones, a well developed, 
spinulose meshwork or crests in the blade (PI. XIX. Fig. 40). Also the shape of 
these larger pedicellariæ is somewhat different from what is found in the other spe- 
cies, the outer widened part being relatively larger. The smaller forms are as in 
the other species. — The spicules do not differ from those of the other species; 
this also holds good of the colour. 
A young specimen (from South Georgia) of 12 mm. length (PI. X. Figs. 1, 3) 
shows already all the characters of the species typically developed, being very dif- 
ferent from specimens of cavernosus of a corresponding size (cf. PI. IX. Figs. 7, 9). 
This decidedly points towards the specific distinctness of the present form. Even a 
specimen of 6 mm. length (likewise from South Georgia) looks rather different from 
cavernosus of a corresponding size — though it may, upon the whole, scarcely be 
possible to distinguish with certainty very young specimens of the different species 
of Abatus. 
This species was taken by the Swedish South Polar Expedition at Station 19 
(5414' S. 30°3i' W. 10 — 15 m. South Georgia), 5 specimens, and Station 33 (54°22' S. 
3Ö°28' W. 22 m. South Georgia), 1 specimen. The specimens from the Hamburg 
Museum likewise came from South Georgia. From the »Revision of Echini» it 
may be concluded that it occurs also at the Patagonian (and Chilian?) coast. It 
appears to be a strictly littoral species. — The A. elongatus was found at the 
South Orkneys. 
Tripylus excavatus Phil. 
PI. XI, Figs. I, 14, 16. PL XII, Figs. 2, 4, 6, 9. PI. XIX, Figs. 18, 34, 44. 
Tripylus excavatus Philippi. 1845. Beschreibung einiger neuen Echinodermen. Arch. f. Naturgesch. I. 
p. 344. Taf. XI, Fig. I. 
— A. Agassiz. 1872. Revision of Echini, p. 169, 588. PI. XXI. c, Fig. 4. 
— — — 1874. »Hassler» Echinoidea, p. 22. 
