148 Transactions.—Zoology. 
the sucker, but a little to one side. The margin of the sucker has a 
horny ring with small teeth more strongly marked on the higher than on 
the lower side. From the base of each pedicel a raised band runs across 
the brachial membrane to its edge. 
Tentacles.—The tentacles vary in length relatively to the body, but 
when thrown back and fully extended often reach beyond its extremity. 
They are oval in section, except at the clavate portion where they are 8- 
angular. The suckers are similar to those on the arms, but are arranged 
in alternating rows of four, are larger and have the horny ring more 
strongly marked. A membrane, similar to that on the arms, is developed 
on each side of the acetabular surface. 
Fach tentacle has a muscular band attached for a short distance near 
its base and widening into a web which connects it with the inner wall of 
the tentacular sac. The sac is not large enough to receive more than a 
short portion of the tentacle, and probably contraction is limited to the 
extent of the muscular band. 
Oral Surface.—The outer lip or buccal membrane (pl. iii. a) is a simple 
membrane with seven marked angles, showing the points of attachment of 
brachial frena. The structure here is very similar indeed to that deseribed 
by Professor Owen as occurring in Loligopsis ocellata (Trans. Zool. Soc. of 
London, vol. xi., pt. v.). Of the frena, the first springs from the small 
basal web between the arms of the first pair; on each side of this is one 
springing from between the second and third arms; next one springing 
from the base of the acetabular surface of each third arm; then a similar 
one from each fourth arm. The surface of the buccal membrane is 
smooth. i 
The inner lip (pl. vii., fig. 1a.) is thick and muscular, and its border is 
marked by strong regular corrugations. f 
The whole surface of the head and body is richly spotted with chroma- 
tophores. They extend over the anterior surface of the fins, but only a 
short distance from the body on the posterior surface. They extend along 
the peripheral surface of the arms, and even along the surface of the first 
three brachial frena. They oceur sparingly on the acetabular surfaces of 
all the arms, and on the peripheral surface of the tentacles. There are 
none on the funnel. 
Microscopic Structure of the Integument. l 
The chromatophores, when examined under the microscope, show, as 
prevailing colours, black or very deep brown, chocolate-brown, cloudy- 
purple, full pink, and pale yellow. Each chromatophore appears to have 
around it a few loose muscular fibres ; and at times I have fancied I have 
detected a loose transparent capsule, with muscular fibres in its walls. In 
