The Norw. North-Atlantic Exped. 
5 
When the animal, by its contraction, shortens itself, the inte- 
gument becomes strongly folded, both longitudinally and trans- 
versally, and acquires a chequered appearance, and the suckers 
then come prominently out in the checks. The movements of the 
animal consist, otherwise, of prolongations and shortenings, expan- 
sions and contractions of the body, but the posterior extremity 
is never retracted into the body. The animal lives in the sand of 
the stony bottom, and from what I observed, whilst I had it alive some 
time in the glass vessel, it rolled about on the surface of the sand 
and did not burrow into it. Only now and then did it raise the 
anterior part of the body and extend the tentacles vigourously, 
whilst the oral disc projected itself prominently forward; but in 
general it lay extended on the surface of the sand and rolled itself 
to the sides. 
The colour. The anterior part of the body is almost pel- 
lucid, with a reddish play of colour; the medial part is flesh- 
coloured, with lighter coloured longitudinal stripes; and the post- 
erior part has, when expanded, about the same colour as the 
anterior part; but when, on the other hand, it is contracted, it 
also is flesh coloured. The oral disc is almost pellucid, with pale 
rosy red rays (folds) having a violet play of colour. The tentacles 
are light red, almost pellucid, and at their base have a brown- 
violet patch which, like a stripe, extends itself along the adoral 
side, right up to the point. 
The external surface of the body is everywhere clad with a 
broad ectoderm, consisting of long ciliating cylinder-cells, with 
nucleus and nucleolus surrounded by a finely granulated proto- 
plasmic mass (Pl. I fig. 6 a, Pl. II fig. 2 a). 
Between the cells . there are, here and there, seen bottle- 
shaped unicellular mucous glands, many of which are filled with 
a finely granulated viscid mass that quite conceals the nucleus, 
whilst others are quite empty. The slightly elongated throat opens 
on to the external surface (Pl. II fig. 2 b). But besides the mucous 
glands, there lie entrenched between the cylinder cells of the ec- 
toderm a great abundance of nematocysts (Pl. II fig. 2 c), which 
are, however, present in the richest abundance on the oral disc 
and the tentacles. Inside of the ectoderm there is a broad layer 
of fibrillar connective tissue (Pl. I fig. 6 b), in whose middle is seen 
a belt, consisting of circular muscle-fibres which appear to collect 
into fine bundles (Pl. I fig. 6 c). From the inner surface of this 
connective-tissue 12 septa issue', standing at a uniform distance 
