Xi) i i 
= ZG : 
Thoracic and abdominal viscera, Ornithorhynchus. 
( Meckel. ) 
Echidna is unprovided with teeth; but the 
palate is armed with six or seven transverse 
rows of strong, sharp, but short retroverted 
spines. The tongue is long and slender as in 
the true Anteaters ; its dorsum is broad, flat, 
callous, and beset with hard papille, and the 
insects are doubtless part Gh and lacerated 
between these and the pa'atal spines. As, how- 
ever, the food undergoes less comminution in 
the mouth of this Monotreme than in that of the 
Ornithorhynchus, the pharynx and cesophagus 
are wider, and a dense epithelium lines the 
inner surface of the latter tube, and is conti- 
nued over the capacious stomach to the py- 
lorus, near which orifice it is ert ss into 
numerous horny and sharp papille. e sub- 
jacent mucous membrane is smooth; the tunics 
of the stomach are very thin, except at the 
pylorus, which forms a prominent protuberance 
in the duodenum. The intestinal canal of the 
Echidna is seven times the length of the body; 
the mugous membrane is not raised into val- 
MONOTREMATA. 
vular folds; a small vermiform and glandular 
cecum divides the small from the large intes- 
tines; the rectum terminates as in the Ornitho- 
rhynchus. 
Salivary glands ——There ap to be no 
rotid gland in the Echidna, and it is doubt- 
ul whether the thin flat stratum of glandular 
substance (fig. 180, E), which extends from 
the meatus auditorius to the check- in 
the Ornithorhynchus, can be so ed. The 
submaxillary gland (fig. 180, D) is a mode- 
rately-sized, oval, compact body, situated be- 
hind and below the meatus auditorius; it mea- 
sured five lines in the long diameter and four 
in the short diameter. The duct is very small, 
scarcely admitting an absorbent as ipe ; 
it passes under the omo-mylo-hyoi eus (10},and 
then, contrary to the usual mode, begins to be 
disposed in a series of about twelve close trans- 
verse folds, and terminates by a single aperture 
at the freenum lingue. 
The submaxillary gland (fig. 188, 5) is of 
unusual dimensions in the idna, in which 
it extends from the meatus auditorius along the 
neck, and upon the anterior part of the thorax: 
it is a broad, flat, oblong lobulated body, nar- 
rowest at its anterior extremity, from which the 
wide duct emerges. When the duct has reached 
the interspace of the lower jaw it dilates, and 
then divides into eight or ten undulating 
branches, which subdivide and ultimately ter- 
minate by numerous orifices upon the mem- 
branous floor of the mouth. This modificati 
which escaped the observation of Cuvier 
M. Duvernoy, appears to be unique. The 
large size of the glands and the mode in which 
the secretion is s over the floor of the 
mouth, relate to the lubrification of the 
slender, and extensible tongue, and to its fit- 
ness as an instrument for obtaining the insect 
food of the Echidna. 
The liver (fig. 187, r, 7) closely retains the 
mammalian type of the organ in Mono- 
tremes. Four lobes may be distinguished in 
the Echidna: the principal or cystic lobe re- 
ceives the suspensory ligament in a fissure; the 
large gall-bladder is placed a little to the right; 
the left lobe occupies the left hypochondrium ; 
the Spigelian lobule is of moderate size; it is 
an appendage of the ng lobe. The liver pre- 
sents nearly the same form in the Ornithorhyn- 
chus, which has likewise a large gall-bladder 
7. 187, ). 
a a are three hepatic duets in the Echidna 
which join the cystic, and the common canal 
terminates in the duodenum pen: more than 
an inch from the pylorus. In the Ornithorhyn- 
chus the two chief hepatic ducts join the cystic 4 
near the neck of the bladder; the third hepatic 
joins a more distant part of the cystic; t 
ductus choledochus receives the atic 
duct about nine lines before its termination, a: 
in the Marsupials, where its coats are thickened 
and glandular, and opens into the duodenum _ 
about eight lines from the pylorus. att 
The pancreas in the Ornithorhynchus is a thin _ 
lobulated gland bent upon itself; the leftand — 
larger portion descends by the side of the left 
ee 
