HV_' TIIK BS8PJBATQST M'I'All I7V> l\ .V.I.V.V.I/./ I 



is lees extensive, hut thicker) ; 4, A hyo-epiglottidean muscle, bitiil at its origin. 1 

 is no arytciio-epiglottidenn ligament.) 



Tlu> trnrhfii of these animals docs not offer any important differences. The lust ring is 

 not ao developed as in the Horse, and the tebe <WMDei a supplementary bronchi; 

 lobe of the lung which does not exist in Solipeds. (Tlie rings of the middle jxirtinn urn 

 proportionally nariow, and their extremities meet In -hind and form a salient ri.L--. 



PIG. The larynx of the Pig Is remarkable for its great mobility, suspended as it is to 

 the hyoid oornua by the base of a very developed epiglottis, rather than by the wi- 

 the thyroid cartilage. "There are wide, shallow, lat-Mal \< utricles, which have a small 

 oblong sinus that ascends between the thyroid curtilage and the mucous membrane. 

 These ventricles ore not surrounded by the thyro-arytenoideus muscle, which is Mnall 

 and undivided; above and outwardly, they are margined by a thick cord a kind of 

 superior vocal cord considered by Duj^es as acting with the ventricles to modify the 

 deep grunting sounds." 1 (Instead of a tnberosity on the external fare of the thyroid 

 cartilage, there is a median crest, and its inferior border lias a small point. The crieoid 

 appears to be drawn downwards and backwards, and its lower bonier is very prominent in 

 the middle, and articulates with one or two small cartilaginous plates which have been 

 sometimes wrongly described as belonging to the proper cartilages of the larynx. The 

 antero-superior angles of the arytenoid cartilages are united to a small cartilaginous 

 piece which prolongs them ; their external face has a spine, and the internal angl- 

 separated by a small pisiform body called the ' intei articular cartilage.") 



The trachea of this animal resembles that of Ruminants. (It has alx>ut thirty rings, 

 and has three bronchi.) 



CARNIVORA. The larynx of the Dog and Cat is very like that of the Horse. In 

 proportion, the epiglottis is shorter, wider at the base, and more triangular than in the 

 other species; the lateral ventricles are shallow. (There is an iiiterarticular cartilap ;<> 

 in the Pig ; there is no sub-epiglottidean ventricle, and the vocal cords appear to be 

 nearer each other. The trachea has about forty-two rings, whose extremities do not meet ; 

 the space between them is less in the Cat than the Dog.) 



The larynx and trachea of Man will be compared with that of animals when we come 

 to describe the lungs. 



THE THORAX. (FigS. 230, 234.) 



The tlwrax, also called the thoracic or pectoral cavity, lodges not only 

 the lungs, but also the heart and the largo vessels that spring from or 

 pass to that organ, with a portion of the oesophagus and trachea, as \vcll 

 as nerves, which are as remarkable for their number as their physiological 

 importance. 



Situation. We have seen that the thorax has for its base the bony cage 

 formed by the ribs, sternum, and bodies of the dorsal vertebrae. Suspended 

 beneath the middle portion of the spine, this cage is transformed into a 

 closed cavity by the intercostal muscles, which fill the spaces between the 

 ribs ; and by the diaphragm, that vast oblique partition which separates the 

 thorax from the abdomen. 



Internal conformation. Considered as a whole, the thoracic cavity 

 represents a hollow cone placed horizontally, depressed on each side, and 

 particularly in front towards the summit ; with its base, formed by the 

 diaphragm, cut very obliquely, in consequence of the direction taken by that 

 muscle. This obliquity of the diaphragm renders the antero-postorior 

 diameter of the cavity muck greater above than below ; the difference is 

 more than double. 



The internal surface of this conical cavity may be divided into six 

 regions : a superior, inferior, and two lateral planes, a base, a posterior plane, 

 and a summit. 



The superior plane presents, on the middle lino, a largo projection 



resulting from the union of the vertebral bodies ; and, laterally, two <livj> 



channels furrows the vertebra- cod 1 <-h<mnch. These latter, wider behind 



than before, are formed by the superior extremities of the costal arches ; 



1 Latocat, ' Anatomic des Auimaux Domestiques.' 



