20 W. BLAXLAND BENHAM. 
My attention was called to this matter in 1894 on examining 
a small Carinella from St. Andrews that happened to be 
amongst a number of specimens of Magelona, which Pro- 
fessor M‘Intosh had most kindly sent to me for the purpose 
of certain work on the latter worm on which I was engaged. 
This Carinella presented, in the hinder region of its body, 
two conspicuous constrictions at nearly equal distances from 
one another, A B, and each piece thus marked out was further 
constricted, though much less deeply, C D, into two nearly 
equal portions (Pl. 2, fig. 1).° So striking was this apparent 
“segmentation ”’ of the body, that I preserved the worm for 
sectionising. It was killed in corrosive sublimate to which 
1 per cent. acetic acid was added. 
Later on in the year, while working in the Marine Labora- 
tory at St. Andrews, with a view to collect and observe living 
Magelona, I came across two more specimens of this same 
Nemertine, which I found living in the sand with the Poly- 
cheete below the ordinary low-water mark. Both these worms 
were about the same size as the one I had obtained previously, 
and both presented similar phenomena of ‘ segmentation.” 
One of these was unfortunately mislaid; the other I killed, 
stained, and mounted entire. 
The Carinella to which these observations refer is a small 
worm about two inches (55 mm.) in length when in moderate 
extension. It is pure white, without eye-spots, and without 
pigment except for a girdle of a faint yellowish-brown colour, 
about a quarter of the worm’s length from the anterior end 
(fig. 1, 6). This is very faint even in life, and is due to pig- 
ment in the epidermis, Further, the proboscis is coloured 
faint blood red for a short region just in front of this pigmented 
band (p). 
The body is nearly cylindrical in section; the head is pointed, 
and slightly marked off from the body by a lateral vertical 
furrow on each side at the level of the mouth; the head is not 
noticeably wider than the body (fig. 2). 
The posterior end of the worm, as longitudinal sections 
showed, is not complete—a portion has already been separated, 
