ALCTONARIA — ,). A. THOMSON AND DOlUS I. MAOKINNON. 169 



merits were taken ; — 323 \ 357 iiiin,; 272 x -255 raui.; -119 x 

 •085 mm. The colour of the majority of the colonies is rt'd- 

 brown ; o'le small specimen is cream-coloured, with very opaque 



spicules. The axis is gieeiii.sh-bron/c, willi fine li,iii;it iiiliinil 

 striations. 



Locality. — South Coast, New South Wales. 



PLUMAHEI-LA V KRSMJ Vsi, .vy, „„,;. 



(Plate IxvL, fii;. 1 ; pi, Ixx lii , liu, J ; pi. I.vxix.) 

 Station 53. 



The largest specimen has a li(!ii,'lit of 225 cm. with a wiilth of 

 about 12 cm. across the btanciied jiortion ; the basal attachnifut 

 is lacking. The branching is confined to one plane, and is 

 typically feather-like. Along each side of the stem and main 

 branches there is a row of twigs alternating with those of the 

 opposite side. The average length of a twig is 2 cm. with a 

 dianietel- of 2 mm.; I here are abont fourteen twigs on eacii side of a 

 branch in a length of 5 cm. Tin; polyps are arranged bilaterally 

 on the larger branches ; on the twigs their arrangement is also 

 lateral, but, a few may encroacli on the middle line Usually 

 they stand in a single row, but occasionally the row is doubled. 



The pol3'ps are of two sizes; the majority are very small, 

 ■75 mm. in length ; here and there occur larger, more swollen 

 polyps, 125 mm. in length. In the smaller polyps the armature 

 consists of overlapping scales, of wliicl.' there are abont four in the 

 abaxial longitudinal rows ; the lateral rows are very indistinct, 

 and the aduxials practically obsolete; the uppermost of each 

 longitudinal row is larger tlmn the rest and projects, so that a 

 slight circumoperculum is formed. The operculum is weil-(lefine<l 

 and conical, formed of eight approximately equal isosceles 

 triangles. The armature of the larger polyps is of the same 

 general type as that just descrihed ; but the longitudinal rows are 

 even less distinct, the polyp scales are i-ather larger and more 

 numerous, and the operculum is low. 



The polyp-scales are broad and fan-shaped, with a distinct 

 nucleus, numerous tnberculate warts, and a clear Anted nnirgin 

 round the part of the sc.ile that projects when on the polyp. The 

 genend appearance of the scales is ver}' similar to those of 

 Plumarelhi Jilicoides, \mt they are markedly thinner, and le.ss 

 heavily sculptured than in that species. The following measure- 

 ments were taken of length and breadth in Mdllimeties : — 

 •425 X -289; 306 x -300; -255 x •187. The opercular scales 

 are similar to those of P. filianiles, but are less strongly ridged — 

 •34 x ^204 mm.; 289 x •l's7 nnn. 



