Isis hippuris Milne Edwards et Haime. Histoire nat. des Coralliaires, Vol. I, 1857, p. 194. 

 Isis hippuris Steenstrup. Om slaegter og de under Isis hippuris Linn. sammenblendedc Arten, 



1848, p. I. 

 Isis hippuris KöUiker. Icones Histiologica;, II, 1865, p. 140. 

 Isis hippuris Thomson and Simpson. Alcyonarians of the Indian Ocean, II, 1909, p. 180. 



Stat. 71. Makassar and surroundings. Up to 32 meters. Mud, sand with mud, coral. 



Stat. 133. Anchorage off Lirung, Salibabu-Island. Up to 7,6 meters. Mud and hard sand. 



Stat. 142. Anchorage off Laiwui, coast of Obi Major. 23 meters. Very fine hard sand, mud. 



Stat. 144. Anchorage North of Salomakiee (Damar) Island. 45 meters. Coral bottom and 



Lithothamnion. 



Stat. 149. Fau Anchorage and lagune. West coast of Gebe Island. 31 meters. Coral. 



Stat. 258. Tual Anchorage, Kei Islands. 22 meters. Lithothamnion, sand and coral. 



Stat. 279. Rumah-Kuda Bay, Roma Island. t,6 meters. Mud and sand. 



Stat. 301. iO°38'S., I23°25'.2E. 22 meters. Mud, coral and Lithothamnion. 



Stat. 303. Haingsisi, Samau Island. Up to 36 Meters. Lithothamnion. 



Colony (incomplete) 28 cm. in height, growing in a densely aggregated mass of branches 

 which are individually composed largely of tufts of branchlets. Main stem, or branch, round in 

 section, about i cm. in diameter. The main branches are lateral in position, often flattened 

 pro.ximally in the plane of ramification. The secondary branches are usually lateral in position 

 and often bear terminal twigs which are swollen, round and pointed at the ends. 



The coenenchyma is very thick and fleshy, and does not show any e.xternal evidence, in 

 alcoholic specimens, of the jointed axis. The calyces are entirely included, and are distributed 

 on all sides of the stem and branches, much as in the Plexauridcc. Their openings are almost 

 completely concealed, appearing only as minute depressions in the general surface of the branches, 

 the openings being no larger than pin holes. In color and appearance the colony greatly 

 resembles a profusely branching JMillepora^ the fine pits closely resembling the gastropores of 

 the latter. The polyps are very minute and entirely retracted, so that little of their structure 

 could be ascertained without sectioning. The surface is quite smooth, the spicules not being 

 evident on account of their small size. 



A cross section of a branch reveals a very thick coenenchyma in which the relatively 

 small calyces are embedded. The coenenchyma is filled with a dense mass of small spicules. 

 Around the axis is a series of very large watervascular canals, their number being very often 

 eight in the smaller branches. The axis is composed of alternate horny and calcareous joints, 

 the latter being the longer and larger, being 1 cm. in diameter in the specimen described. Their 

 length is about i cm., and this does not vary greatly even in the distal branchlets. 



These calcareous internodes are strongly fluted longitudinally, the grooves being the 

 impressions of the primary watervascular canals. The horny nodes are much shorter, not exceeding 

 3 mm. in the specimen described, and having a diameter of 5 mm. where the adjacent calcareous 

 joints are i cm. long. The branches usually arise from the calcareous nodes, but bifurcations 

 usually take place upon the distal ends of horny joints. 



A cross section of a calcareous internode about 5 mm. in diameter shows a central 

 amorphous area surrounded by a darker line, like a line of growth, enclosing a figure with 

 eight concave sides, beyond this, at varying distances, are other similar lines enclosing figures 

 of more than eight concave sides, the outer lines being closer together than the others. While 



