134 
DR. C. H. JONES ON THE STRUCTURE 
Explanation of the Plates. 
PLATE IX. 
Figs. 1, 2, 3, 4 represent cells from the liver of the Earthworm ; (1) and (2) are elon- 
gated and filled with spherules of biliary matter ; the envelope is prolonged 
into a tubular neck in (1.), diameter about x s^oo th of an inch. (3.) has a 
delicate envelope, a nucleus, and some biliary contents, diameter e-g-gth of 
an inch. (4.) has a distinct envelope enclosing only pale granular matter, 
diameter of an inch. 
Fig. 5 is an ideal section of an Earthworm, showing the relation of the typhlosole to 
the cavity of the intestine. The hepatic stratum on the exterior of the in- 
testine is seen to be continuous with that in the typhlosole ; i is the intes- 
tinal cavity ; f, that of the typhlosole ; d, the dorsal vessel in contact with 
/, /, /, the hepatic stratum. 
Figs. 6, 7, 8, 9, 10 are taken from examination of the liver in the Leech. (6) repre- 
sents two cells full of dark biliary contents cohering together. (7) a cell con- 
taining pale amorphous matter in which some biliary spherules have begun 
to appear, diameter of inch. (8) is a cell containing only pale gra- 
nular matter, no perceptible nucleus, diameter e^th of an inch. (9) is a cell 
apparently dissolving ; it has no envelope, and the biliary spherules are 
separating from each other, diameter — of an inch : in the centre 
there is a clear cavity which was observed in many others, as if the minute 
spherules were repelled outwards by some force. (10) a tube with several 
irregular bulgings, indicating the coalescence of the component cells ; one 
cell is seen lying close by the side of the tube, but not yet united to it : the 
envelope of this tube was very faint in most parts ; it almost resembled a 
solid tract of biliary matter. 
Fig. 1 1 . An hepatic tubule from the Blowfly {Musca vomltorid) ; it seems to be made 
up of a series of vesicles which overlie each other: the outlines of all are 
extremely distinct, and they all communicate together, being traversed by 
a central canal. It is not certain whether the first vesicle be truly the 
origin of the tube, or whether it has been detached from others with which 
it was in connection ; there can, however, be no doubt that the specimen 
represents a tube very near, if not quite at its origin. The basement tissue 
of the tube was very conspicuous ; it enclosed a great quantity of yellowish 
granular matter, in which were imbedded some transparent cells. In some 
parts of the central canal there were patches of opake oily matter ; the dia- 
meter of the tube at its origin was of an inch ; near its lower part 
y^rd of an inch. 
Fig. 12. Portion of hepatic tube from large white Moth ; its diameter is ^o^h of an 
