SEA-FISHERIES LABORATORY. 193 
piece of the tissues of this fish stained with borax-carmine, 
cleared, and mounted in balsam. The black particles are 
seen to be round or oval egg-shaped structures, and they 
consist apparently of concentric shells of some structure- 
less substance arranged round a nucleus. They may be 
compared with pearl-like concretions. -Kach of them, or 
sometimes two together, are surrounded by a kind of 
capsule, and the row, six in this case, is surrounded by a 
loose connective tissue. The whole les between the 
muscle fibres, which have been forced apart. 
feo ei Lil, represents part of a section, made 
transversely to the muscle bundles, and stained with 
Mann's methyl-blue-eosin. It shows one of the black 
particles cut nearly through the centre, and lying among 
a group of muscle fibres. These bodies vary much in 
size and shape. Generally their diameters range from 
0°39 x 0:15 mm. to 028 x 022 mm. They are usually 
ego-shaped. It is seen that each consists of a nucleus 
which has no definite structure, being composed entirely 
of granules, large and small, with sometimes masses of 
pigment, and sometimes highly refringent larger granules. 
Surrounding this nucleus are a variable number of 
concentric shells, made up of a substance showing no 
regular structure. These shells are occasionally rather 
widely separated, and the spaces between them often 
contain finely granular matter. Outside this highly 
pigmented concretion is a shell of fibrous tissue, 
apparently belonging to the intrusive body; and outside 
this again is another looser shell of fibrous tissue, looser 
in structure, and consisting of fine wavy bundles. In 
fig. 2 these are seen end on. Scattered among them are 
small nuclei. This part evidently belongs to the tissues 
of the host, and is an investment, protective it may be, 
and probably producedas the result of local inflammation. 
