9 
1. Stylaster eximtus Duchassaing and Michelotti. 
S. elegans Duchassaing and Michelotti. Les Coral. des Antilles. Supplement p. 68, Pl. IX. 
fig. 4. 1864. Name of species preoccupied, renamed as follows: 
S. eximius Saville Kent. Proc. Zool. Soc. Lond. April 4th 1871. 
S. duchassaingii Pourtales. Deep-Sea Coral. 1871, p. 35, Pl. VI, fig; 1 and) 2. 43 fms, 
Tortugas. 
The greatest depth at which the specimens which are grouped round the species 5S. 
extmtus, in the Siboga collection, have been found is 118 M. (65'/, fms.). The least depth at 
which, in this collection, an old or new distinct species has been found is 204 M. (S. bclobatus). 
It is especially interesting to note that this species recorded at 204, 469 and 520 M. varies, 
to not a small extent, with these localities and the specimen that comes from 204 M. is the 
least specialised and most closely related to S. exémius. The large species S. eximdus has 
been divided into a number of facies. 
a. S. eximius fac. altus. Plate I, figs. 1—3. 
Stat. 164. 1°42'.5S., 130°47’.5 E. W. of New Guinea. 22 M. 2 pieces. 
Stat. 144. S. of Halmaheira. 45 M. Several small pieces. 
Stat. 282. 8°25'.2S., 127°18'.4 E. E. of Timor. 27—54 M. or from reef. 1 fragment. 
Stat. 303. Between Timor and Samau Ils. Up to 36 M. Several pieces. 
This is a tall, subflabellate coral with non-anastomosing branches (Fig. 1). The height 
is about 100 mm., the diameter of the main stem at its base 3 mm., the axis at the base of 
the terminal branches from 0,8 to 1 mm. The colour is white, but one branch among the 
many pieces from Stat. 303, was faintly suffused with pink in certain regions, which included 
some side branches, about the middle of its length. The surface of the hydrophytum, including 
the ampullae is smooth, but fine longitudinal striations caused by rows of vertical canals of 
the coenosare can be seen under magnification on the younger branches. The bracket-like 
cyclosystems (Fig. 2—3) are small, being from 0,7 to 0,8 mm. in transverse diameter and 
projecting 0,4 mm. from the surface. Alternate cyclosystems, that is to say adjacent ones on 
the same side of the stem, are about 1—6 mm. apart. 
The method of growth appears to be influenced considerably by the production of 
ampullae. A great production of gonads seems to retard growth in length; the thickness of 
the branches increases considerably; the cyclosystems seem to become relatively smaller and 
less important, they project less, that is to say, are less bracket-like and are often joined 
(cf. S. de¢/us). When this is the case, fresh dactylozooids may be formed so as to complete the 
cycle (Fig. 3). Colonies are often found in a transition stage, but one old, dark-coloured 
specimen from Stat. 282 has almost entirely complete cylosystems, with joined septa, and these 
cyclosystems, in the older parts of the stem, lie flat on the surface and gradually become 
quite overgrown by the coenenchym. On the younger branches the lower, abaxial edge of 
the cyclosystem projects slightly. 
The specimen drawn and described by Ducnassainc and MicneLorit probably belongs 
2 
SIROGA-EXPEDITIE VIIL. 
