258 DR. C. A. MAC MUNIST ON ENTEROCHLOROPHYLL, AND ALLIED PIGMENTS. 
occurring in granules, singly and in aggregates, some of which are round, the pigment 
is also dissolved in oil globules and may be present in the diffused condition. USTo 
unicellular algse can be seen.* * * § (See Plate 10, tig. 2.) 
In Uraster the smaller coecal tubes are seen packed with oil globules of a yellow 
colour, some of which are very large, and this appearance is so constant that I think one 
would be correct in assuming that here the enterochlorophyll is mainly dissolved in oil. 
In Patella, sections show the tubes of the “ liver ” cut in various planes, the pigment 
occurring mostly in very fine granules of a yellow colour, and as in Ostrcea it is distributed 
along the periphery t of the tubes, sometimes in the diffused state. Some yellow oil 
globules are also seen. The granular pigment appears to be confined to the epithelium 
cells lining 1 the tubes. 
In Littorina, the “ liver " itself has the same kind of structure, but so little connective 
tissue holding the tubes together, that the sections readily fall to pieces. The entero- 
chlorophyll occurs in very small granules, of an orange colour, in small round cells, 
and in oil globules, some of which have a greenish tint. On the whole, it appears 
confined to the periphery of the tubes. (See Plate 10, fig. 1.) 
In Purpura lapillus, the amount of pigment is very small, and of a pale-yellow colour; 
the epithelium lining the periphery of the tubes seems to contain the pigment mostly 
in a diffused condition. 
In LimncBUS stagnalis the enterochlorophyll occurs in round and angular minute 
granules, also in oil globules, some of which are yellow, others a more pronounced 
green. Coloured cells of an epithelial type, some of which enclose granules, and others 
diffusely stained with the colouring matter, are also found. These latter are doubtless 
the epithelial lining cells of the “liver” tubes. (Plate 10, fig. 4.) 
In Helix pomatia the enterochlorophyll is found in granules and oil globules ; also 
in peculiar cells probably of an epithelial type, some of which contain granular pigment, 
and others are diffusely stained of a green and yellow-green colour. The latter pro¬ 
bably belonging to the lining of the cell spaces of the “ liver. 
In Helix aspersa :§ the appearances are much the same, but the large round brown • 
bodies are very peculiar (see Plate 10, fig. 5). It would seem that the latter are coloured 
by theheematin constituent of the “bile”; the enterochlorophyll occurs in the periphery 
of'the cell spaces and in their epithelial lining. The large brown cells measured from 13 /x 
in diameter to 15 /x, other yellowish-brown cells from about 8 /x to 4 /x, down to 1 ^ /x. 
There are green oil globules 8^ p in diameter, some 5^ /x of a yellow colour, others 
are coloured by a mixture of yellow, green, and brown, measuring 4 /x and some 2 /x. 
Tire brown bodies do not lose their colour when extracted with alcohol, while the 
* In Mytilus edulis the pigment occurs very richly in round brownish-yellow granules, also in small oil 
globules. 
"f J.e., in tbe secreting cells. 
J In the “ bile ” certain spherical crystalline bodies are seen which I hope to examine shortly. 
§ I am rather inclined to the belief that in Helix and Limax after feeding some food chlorophyll is 
taken up into the “ liver.” 
