2 I I 
Family Isidae. 
Sub-family Isidinae. 
Genus Isis. 
i. Isis hippuris L. (Plate V, Fig. 3). 
For description see: THOMSON and SlMPSON, Alcyonarians of Indian Ocean, 1909, p. 181 — 191 , 
3 figs- 
Stat. 258. Tual-anchorage, Kei-islands. Reef. 1 Ex. 
Stat. 303. Haingsisi. 36 M. 1 Ex. 
A small colony of this well-known species, rising to a height of 4 cm. with an average 
breadth of 3 mm. There is an expanded cup-shaped base, evidently fitting over a substratum, 
and there is some hint of a basal branch having been broken off. The specimen seems in 
every way typical; the spicules are very characteristic. 
A fragmentary specimen from Haingsisi is also typical. 
Previously recorded from Pacific Ocean, Indian Ocean, Mediterranean Sea, /America, 
North Sea, Iceland, Antilles, Straits of Sunda and Southern Coast of Sumatra, East Indies, 
and Amboina. 
Also from Siboga Stations 71, 133, 142, 144, 149, 258, 279, 301, and 303. 
Sub-family Muricellisidinae. 
Genus Muricellisis. 
1. Muricellisis cervicornis n. sp. (Plate VII, Fig. 8; Plate XXI, Fig. 12). 
For description of genus see: KUKENTHAL, Wiss. Erge'on. Deutsch. Tiefsee Exp. XIII, 1919, 
p. 626, 6 figs. 
Stat. 139. o°li / S., I27°25 / E, 397 M. Mud, stones and coral. 1 Ex. 
An interesting fragment of a whitish colour, with faintly yellow nodes, is referable to 
Kukenthal’s little known P’enus Muricellisis for the following- reasons : 
(1) the long amorphously calcareous internodes are separated by short partly horny nodes (thus 
indicating Isidae); 
(2) the polyps are retractile into low calyces (thus excluding Ceratoisinae and Mopseinae); 
(3) the polyp spicules are very rough spindles, and not small warty irregular bodies (thus 
excluding Isidinae). 
Our specimen agrees then with Muricellisis in the following points : the polyps are retractile, 
and show a distinct calyx; the sclerites are very rough spindles. In more detail, the internodes 
are long, e. g. 1 cm., with fine sloping striation, thumb-print-like; the nodes are very short, 
about 2 mm.; the calyces arise all round; their wall is supported by irregularly arranged, yet 
on the whole longitudinal spindles; the armature of the polyp consists of eight double rows 
(often 2 — 3 pairs) of sloping spindles, rising from a horizontally disposed crown of 2 — 3 rows; 
the tentacles are well armoured and form a pseudo-operculum. 
