HOYLE: REPORTS ON THE CEPHALOPODA, DD 
1. The Posterior Cup presents an outer coating of brown pigment (c.) which, 
however, is neither so thick nor so dense as that of the ocular organ. The 
scales composing the cup (p. c.) are thicker and more closely paeked, and. the 
connective tissue lying between them is more delicate. Most of the sections 
of this organ which I examined had been stained with carmine, and this fact 
may account for an apparent difference in the composition of the scales. They 
present a granular appearance, but do not show traces of a network like that 
described above. The form of the scales, judging by an examination of tan- 
gential sections, seems to be much less regular than in those above mentioned. 
They give off processes which branch, and in some cases almost appear as 
though they joined one scale with another, though I hardly think that such is 
the case. A somewhat oblique section, through the cup and the central knob, 
is shown in Fig. 8, and exhibits very clearly the concentric arrangement of the 
scales round the central knob. 
2. The Inner Cone (i. c.) presents very little difference from that of the 
ocular organs except that the fibres composing it are more delicate. In some 
of the sections, they show a tendency to curve round the outside edge of the 
central mass, but this appearance I imagine is due to the sections not being 
cut exactly through the centre. In some places I detected a nerve passing 
through the inner cone in the same way as in the ocular organ. 
3. The Oentral Mass (c. m.) is in general form intermediate between that 
of the ocular organs just described and that of P. margaritifera. It resembles 
the latter in the fact that it has no scales in its centre, and that it does not 
show distinet cell outlines, whilst in the fact that it extends as far as the rim 
of the inner cone it presents a likeness to P. giardi. It is made up of finely 
granular substance which stains only very faintly. The nuelei are very few 
and far between in the central knob, but are much more abundant towards 
the base of the conical portion, where many of them seem to be elongated in 
the direction parallel to the base of the cone. 
4. The Anterior Cap (a.c., a.c.) is made up of two layers of about equal thick- 
ness, but whereas in the ocular organs the deeper layer is composed of delicate 
fibrils and the more superficial of large scales, in this instance the scales are in the 
deeper part, whilst the fibrous portion is above. The scales differ from those of 
the posterior cup inasmuch as they show a marked tendeney to become resolved 
into fibres (Fig. 7). One or two of the larger ones, however, show no fibres, 
but simply a granular structure similar to those of the posterior eup, but more 
pronounced. The superficial layer is almost homogeneous, but there can be 
seen in it delicate striations which run for the most part parallel with the sur- 
face. They are more clearly marked and less wavy in the deeper layers. 
The nuclei are fairl y abundant and are fusiform in shape, with their long axes 
parallel to the direction of the fibres. 
5. The Collar (co.) is the structure whose presence most clearly distin- 
guishes the siphonal from the ocular organs. It surrounds the organ parallel 
with its equator just opposite to the deeper layer of the anterior cap. It is 
covered by the connective tissue capsule of the organ and in minute structure 
