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AREOLAE TISSUE, TENDONS, AND MUSCLES. 213

ing into the lachrymal sac, though they may open by one common duct.
They are lined by pavement epitheHum. They pass to their termina-
tion imbedded in connective tissue and surrounded by longitudinal
fibres of the concentric or ciliary portion of the orbicularis palpebrarum
muscle, and empty by independent openings into the lachrymal sac.
Occasionally these canals merge into one another and terminate in one
common duct. They are lined by pavement epithelium.
The Superior Lachrymal Canal is smaller in calibre than the inferior,
though it. is slightly longer, being nearly five lines in length and two
lines in width. It commences on the inner margin of the upper eyelid,
curves slightly upward, inward, and downward, and enters the orbital
•aspect of the sac a little below its summit.
The Inferior Lachrymal Canal is somewhat thicker and shorter than
the superior. It commences at the inner margin of the lower eyelid,
passes slightly downward, inward, and upward, and enters the lachrymal
sac just below the superior canal.
The Lachrymo-naaal Passage is divided into two portions, the sac
and the duct, the latter being lined by a ciliated epithelium similar to
that of the nose.
The Lachrymal Sac is the upper enlarged portion of the lachrymo-
nasal jmssage, and is situated in the sulcus formed by the upper portion
of the lachrymal grooves in the lachrymal and superior maxillary bones.
It is retained in position by connective-tissue fibres which unite with the
periosteum of the bone, and by fibres with the internal tendo-palpe-
brarum and tensor tarsi. The sac is about half an inch long, being
a little M'ider than long at its broadest portion. It is flat on its inner
surface, which is that portion next the bone, but its external surface,
or that next the orbit, where the canaliculi find entrance, is rounded
and projects toward the eye. The superior portion of the sac is dome-
shaped, while the inferior portion is smaller and passes into the nasal
duct without any line of demarcation between them.
The Lachrymo-naml Buct is formed by the lower portion of the
lachrymo-nasal passage. It is slightly over half an inch in length, and
extends from the lachrymal sac into the inferior meatus of the nose by
passing through the lachrymal canal. The duct is larger at its extrem-
ities than in "the middle, and is adherent to the bony walls, through
which it passes, by connective-tissue fibres uniting it with the periosteum.
Valve-like folds of the lachrymo-nasal ]iassage have been described
as existing at the openings, Avithin the canaliculi of the sac, in the duct,
and at its termination in the nasal chamber.

The Tonsils.
The Tonsils (tonsillffi amygdala?) are two glandular bodies situated on
each»side of the oro-])haryngeal space, which is in relation in front with
the palato-glossal fold (anterior palatine arch) ; behind, with the palato-
pharyngealfold (posterior palatine arch) ; laterally, with the constrictor
muscles of the pharynx ; and proximally or internally it is open, this
surface being covered by the mucous membrane of the oro-pharyngeal
space above referred to.' The fact that the palato-glossal and palato-