ALCYONAKIANS. — BRIGGS. 75 



MoPSEA WHiTELEGGEi, Tkomsou and Mackinnon. 



Mopsea whiteleggei, Thomson and Mackinnon, Mem. Austr. 

 Mus., iv., 13, 1911, p. 678, pi. Ixvi., figs. 2, 3, 

 pi. Ixxiii. 



Two well-preserved specimens, referable to this species, 

 were obtained from the same locality. The larger of the two 

 rises from a slightly encrusting base to a height of 26 cm., 

 with a width of 20 cm. across the expanded portion. Branch- 

 ing begins at a height of 25 cm. from the base, and is typically 

 plume-like ; the branches are confined almost entirely to 

 one plane. The stouter branches have an average diameter 

 of 2 mm., and the twigs of 1 mm. near their tips. The second 

 specimen is 21-5 cm. high, with a spread of 16-5 cm. across 

 the branched part. 



The diameter of the axis near the base is 3 mm. The 

 ■coenenchyma has worn a^vay from this portion of the stem, 

 and the axis shows the white calcareous internodes with fine 

 longitudinal ridges, and the amber-coloured nodes. The 

 twigs arise from the calcareous internodes. 



The polyps are arranged alternately in a single row along 

 the twigs, here and there encroaching on the middle line and 

 becoming irregular in disposition. They are club-shaped, 

 with truncate mouths, and turn up^^ards towards the ex- 

 tremity of the twig. The average length of a polyp is about 

 -6 mm. 



The spicules are (1) small, colourless, flattened spindles and 

 curved lancet-shaped plates, produced more strongly on one 

 side of the spicule than on the other into a number of tooth- 

 hke warts— 262 x -052 mm. ; -245 x -052 mm. ; -175 x 070 

 mm.; •131x087mm.; (2) small spindles and club-like 

 forms — -131 x-026 mm. ; -122 x-035 mm. ; -096 x-03o mm. ; 

 •087 X -035 mm. ; -052 x -026 mm. 



The colour of the colonies is creamy-white. 



Locality. — Six miles 8. 30° E. of Brush Island, New South 

 Wales, 65 fathoms. 



Distribution. — Hitherto known only from '' Thetis " speci- 

 mens taken off the coast of New South Wales at the following 

 localities : — Eleven miles east of Broken Bay ; Station 10, 

 off Broken Head, 28 fathoms ; Station 40, off Wata Mooli, 

 52 fathoms ; Station 44, off Coogee, 49-50 fathoms ; 

 Station 48, off Wollongong, 55-56 fathoms (Thomson and 

 Mackinnon). 



