550 RESPIRATORY SYSTEM OF THE DOG 
outward from the septal cartilage in the floor of the nostril, and another lamina 
supports the alar fold of the ventral turbinate bone; these may be termed accessory 
nasal cartilages (Cartilagines nasi accessorize). 
The length of the nasal cavity varies greatly in different breeds, correspond- 
ing, of course, to the length of the face. The cavity is roomy, but is very largely 
occupied by the turbinates and the lateral masses of the ethmoid bone. The 
middle meatus is short and narrow, and divides posteriorly into two branches: the 
upper branch leads to the ethmoidal meatuses; the lower branch joins the ventral 
meatus. The ventral meatus is very small in 
its middle part, owing to the great develop- 
ment here of the ventral turbinate. The 
posterior part of the nasal cavity is divided 
by the lamina transversalis into an upper olfac- 
tory part and a lower respiratory part. The 
sinuses have been described (vide Osteology). 
THE LARYNX 
The larynx is relatively short. The lamina 
of the cricoid cartilage is wide; the arch is 
grooved laterally. The lamine of the thyroid 
cartilage are high, but short; they unite ven- 
trally to form the body, on which there is an- 
teriorly a marked prominence, and_ posteriorly 
a deep notch. The oblique line on the lateral 
surface of the lamina is prominent. There is 
a rounded notch (Fissura thyreoidea) below the 
short anterior cornu for the passage of the an- 
terior laryngeal nerve. The posterior cornu is 
strong, and has a rounded surface for articula- 
tion with the cricoid cartilage. The arytenoid 
cartilages are relatively small, and have between 
them a small interarytenoid cartilage. The 
Fic, 490.—Avitus Laryncis anp Retate>  epiglottis is quadrilateral; its lower part or 
Sravengans ox) on) stalk (petiolus) is narrow, and fits into the 
alae the wia-dérsal line and reflected: angle of the thyroid cartilage. The cuneiform 
1, Epiglottis; 2,2, corniculate cartilages; cartilages (Cartilagines cuneiformes) are large 
es; 4, glottis; 5, wall of and somewhat crescent shaped; they are not 
The pharynx and cesophagus have been cut 
8, 3, arytenoid cartil 
pharynx; 6, cesophagus; ih ienen Cason 8s mised anti the epiglottis. 
posterior pillar of soft palate; 9, median suleus . ‘ 
of tongue; 10, vallate papille; 17, conical pa- The false vocal cords extend from the 
pille of root of tongue; 12, 12, tonsils (shown ¢yneiform cartilages to the thyroid. The true 
by opening up tonsillar sinus), 3 
vocal cords are large and prominent. The 
large lateral ventricle is a long slit parallel with 
the anterior margin of the true vocal cord. The laryngeal saccule is extensive and 
lies lateral to both true and false vocal cords. 
The crico-thyroid muscle is thick. The hyo-epiglotticus is well developed, 
and is double at its hyoid attachment. The ventricularis or anterior part of the 
thyro-arytenoideus arises on the cuneiform cartilage. Hence Lesbre has suggested 
the name cuneo-arytenoideus for it. 
THE TRACHEA AND BRONCHI 
The trachea is practically circular in cross-section at its ends, but the inter- 
vening part is very slightly flattened dorsally. It contains about forty to forty- 
