122 DR A. MILNES MARSHALL ON THE 



Of this very variable species Kolliker distinguishes three well-marked 

 varieties, characterised as follows : # — 



1. Var. angustifolia : Leaves long and narrow; polyp heads few and wide 

 apart. 



2. Var. lancifolia : Leaves lancet-shaped ; polyp heads numerous, and close 

 together. Of this form, which should probably be considered the typical 

 P. phosphorea rather than a distinct variety, Kolliker further distinguishes 

 four sub-varieties. 



3. Var. aculeata : Leaves slender, and placed close together ; on the ventral 

 surface of the rachis are four to six rows of long spines, connected with the 

 zooids. 



Of the " Triton " specimens those obtained off the Butt of Lewis belong to 

 the second variety lancifolia; while the more numerous specimens from the 

 deeper water of Station 11 are typical examples of the variety aculeata. The 

 two forms are so distinct that it will be well to describe them separately. 



P. pliosyliorea var. lancifolia, Koll. 



All four specimens are small, and of somewhat stunted appearance, the 

 leaves being twisted in an irregular manner, so that sometimes the dorsal and 

 sometimes the ventral border of the leaf is turned upwards. The four speci- 

 mens, though of nearly the same absolute size and all obtained at one haul, 

 differ a good deal among themselves as to the shape of the leaves and the 

 breadth of their attachment to the rachis, and also as to the extent of separa- 

 tion between the component polyps of a leaf. 



The zooids, which are uniform in size, cover the whole ventral surface of 

 the rachis, except the mid-ventral groove, and extending upwards between 

 the leaves, become continuous with small groups of three or four zooids each 

 situated on the dorso-lateral angles of the rachis between the leaves. 



In all four specimens the stalk, with the exception of the terminal dilatation, 

 which is yellowish, is of a dark red colour, due, as in the rachis and leaves, 

 to the calcareous spicules imbedded in it. In one specimen the colour is a deep 

 purple of exceptional intensity. 



The measurements of the four specimens in millimetres are as follows : — 



Length of colony, 



„ rachis, 



„ stalk, 



„ leaves, 

 Greatest width of leaves, 

 No. of leaves on each side, 

 » polyps per leaf, 



* Kolliker, Anatomiich-systematisclie Beschreihung der Alcyonarien, pp. 130-134. 



A. 



B. 



C. 



D. 



60 mm. 



56 mm. 



58 mm. 



58 n 



31-5 



27 



31 



30 



28-5 



29 



27 



28 



13 



13 



12 



115 



2 



2-5 



3 



3 



20 



21 



22 



20 



10 



9 



9 



10 



