12 



anchylosed with the substance of the jaw. The tongue is 

 fleshy, well-developed, with the apex more or less free. The 

 posterior nares are protected by a soft palate, and the larynx 

 by an epiglottis : the rings of the trachea are generally carti- 

 laginous and incomplete behind : there is no inferior larynx. 

 The oesophagus is continued without partial dilatations to the 

 stomach, which varies in its structure according to the nature 

 of the food, or the quantity of nutriment to be extracted there- 

 from. 



The trunk- vertebras of Mammalia have their bodies ossified 

 from three centres, and present for a longer or shorter period 

 of life a discoid epiphysis at each extremity. They are arti- 

 culated by concentric ligaments with interposed glairy fluid 

 forming what are called the intervertebral substances; the 

 articulating surfaces are generally flattened, but sometimes, as 

 in the necks of certain Ruminants, they are concave behind 

 and convex in front. The cervical vertebras are seven in 

 number, neither more nor less. The lumbar vertebras are 

 more constant and usually more numerous than in other 

 classes of vertebrate animals. The atlas is articulated by 

 concave articular processes to two convex condyles, which 

 are developed from the ex-occipital elements, or neurapo- 

 physes, of the last cranial vertebra. The tympanic element 

 of the temporal bone is restricted in function to the service 

 of the organ of hearing, and never enters into the articula- 

 tion of the lower jaw. The olfactory nerves escape from 

 the cranial cavity through numerous foramina of a cribriform 

 plate. The optic foramina are always distinct from one 

 another. 



The scapula is generally an expanded plate of bone ; the 

 coracoid, with two (monotrematous) exceptions, appears as a 

 small process of the scapula. The sternum consists of a 

 narrow and usually simple series of bones : the sternal por- 

 tions of the ribs are generally cartilaginous and fixed to the 

 vertebral portions without the interposition of a distinct arti- 

 culation : there are no gristly or bony abdominal ribs or 



