26 DR J. STEPHENSON ON 
As will be seen, these two varieties shade into each other, the purple having 
frequently a brownish, and the brown a purplish tinge. 
(iii.) The rarest variety is the green, of which specimens were obtained from an 
island in the harbour, and also from Fairlie sands. ‘he colour may be a light green 
throughout ; or it may be darker, with a bluish tinge anteriorly ; or it may be a light 
olive, becoming reddish anteriorly (not due to the colour of the ganglia); or, finally, it 
may be a dark olive green, with a faint appearanee of longitudinal stripmg. One 
specimen showed a white constriction at about the middle of its length ; and a number 
showed a pale lateral stripe along the margins of the body. 
Here, again, the mention of ‘olive’ shows the tendency to a brown coloration ; but 
the green variety is, on the whole, much more sharply marked off from the others than 
the purple and brown from each other. 
In all varieties the margins of the head are pale. The numerous pale transverse 
wrinkles mentioned by MaclnrosH were as often absent as present. 
The head is somewhat flattened, and is marked off from the succeeding part of the 
body by slight notches. It narrows slightly, but only slightly, towards the anterior 
end, so that this extremity has a truncated appearance. In a few specimens a minute 
ciliated papilla was seen at the centre of the anterior end, and once a slight indentation 
was noticed at this spot; usually neither was visible. The well-marked lateral grooves 
extend from the notches forwards to nearly the anterior end of the head. 
I have paid some attention to the comparative width of head and body in these 
forms, since this character is here, as in many other species of Nemertines (cf avt., on 
LL. longissimus), commonly used as a diagnostic mark. I find that the head may be, at 
its widest part, either very slightly broader, or no broader, than the succeeding part of 
the body. MaclInrosu’s expression on this point is that the head is “ distinctly wider 
than the rest of the body,” or ‘‘ decidedly wider than the succeeding part of the body.” 
BorGER defines it as ‘“‘ein wenig verbreitert.” 
The eyes vary in number from one to five on each side, or three to eight 
altogether. They are in the majority of cases situated in a regular longitudinal row at 
the upper edge of the pale lateral margin of the head, the anterior eye on each side 
being the largest. These two are symmetrically arranged, but the succeeding eyes are 
usually not symmetrical, nor the same in number on the two sides. 
The mouth is an elongated median slit, situated in a pale oval area, behind the level 
of the lateral notches. The proboscis reaches back about one-third of the animal's 
length. The intestine gives off small simple or bifurcated diverticula. 
BurGerR unites under LZ. ruber (MULx.) both L. gesserensis and L. sanguineus, 
described as separate species by MacIyrosu. Journ does the same, his first three 
colour varieties corresponding to L. gesserensis, his last two to L. sanguineus. 
sesides their colour, the two species gesserensis and sanguineus have been stated to 
differ in the comparative width of head and body, in the disposition of the eyes, and in 
their habits ; and it is interesting to note that, while agreeing in colour with gesserensis, 
