136 
DR. C. H. JONES ON THE STRUCTURE 
Fig-. 20. 
Fig. 21. 
Fig. 22. 
Fig. 23. 
Fig. 24. 
Fig. 25. 
envelope, and contain 3-5 circular or oval vesicles, which have somewhat 
the aspect of nuclei : the whole group of cells are imbedded in a collection 
of yellow granules of rather large size. 
One of the vesicles occurring in the parenchyma of the Skate’s liver. The 
central cavity is shown with traces of surrounding laminae concentric to 
the envelope, between which are some small vesicles : long diameter about 
3^th of an inch ; short 4^th of an inch. 
A rather large branch of the hepatic duct, diameter y^th of an inch ; its 
walls consist of homogeneous membrane with investing fibrous tissue ; its 
cavity is filled with nuclear granules, finely granular matter and oil-globules ; 
from its side there springs off a minute branch, which tapers evenly to its 
termination ; its diameter is xsVofh of an inch ; near its origin it has a di- 
stinct homogeneous tunic and a little fibrous investment ; towards its ex- 
tremity the homogeneous membrane can no longer be discerned, though the 
margins are even and the extremity rounded, and there is not the slightest 
appearance of its having suffered injury ; it is I believe really a terminal 
branch becoming resolved, as many others are seen to be, into a delicate 
tract of granular matter ; in some of these, as in fig. 16 , nuclei are manifestly 
to be found ; in others they are scarcely perceptible, or apparently absent. 
(From Flounder.) 
A large branch of the hepatic duct with several minute offsets ; some of these, 
as well as the main branch, have pretty large yellow masses of biliary matter 
adhering to their exterior. The interior is filled with nuclear granules and 
granular matter. (From Tench.) 
A small, probably terminal, duct from liver of Grass Snake ; it tapers from 
' a oVo ^h to 3-^g^th of an inch ; its extremity is rounded ; no basement mem- 
brane can be discerned ; it seems to consist of nuclei set in a finely mottled 
substance. 
A branch of the hepatic duct, with a minute lateral offset from liver of Duck. 
The parent branch has an homogeneous tunic with fibrous investment ; on 
its interior there is a granular epithelial layer, in which nuclei are but faintly 
discernible ; the offset is Y^th of an inch in length, and of an inch 
wide near its termination ; it gives off no branches ; in the greater part of 
its extent it has a tunic of basement membrane enclosing nuclei dispersed 
through granular matter; its terminal extremity was somewhat obscured, 
being in contact with some remains of parenchyma, but I am inclined to 
think it was closed ; another specimen from the same was distinctly seen 
to terminate by a closed extremity. 
A minute duct from liver of Sheep perfectly isolated from other structures ; 
its diameter is jQ^oo th of an inch, its length of an inch ; it gives off 
no branches ; its extremity appears to be closed ; it has perfectly defined 
