118 DR. C. F. SONNTAG ON THE ANATOMY 



result of coiitractiue of the muscles. It is necessary, therefore, 

 to examine fresh material if one desires to study these characters 

 properly. Speaking generally, the real fissures are regular and 

 symmetrical, or nearly so. They are complete or incomplete, the 

 former extending right across the dorsum, and the latter 

 stretching only from the median fissure to the edges of the 

 tongue. They may be straight or curved, with their convexities 

 forwards. 



In the Lemurs and Marmosets, they are shallow, broad, and 

 curved ; there are one or moi-e complete ones behind the apex, 

 and several incomplete ones behind these on both halves of the 

 dorsum. In the Stoat, the fissui'es are narrow and deep, and 

 they pass in straight lines obliquely forw^ards and outwards from 

 the median fissure to the lateral borders of the organ. 



Tlie arrangement of the papillae on these fissures and ridges 

 varies. In the Stoat they are only on the ridges, but in the 

 Lemurs and Marmosets they are on either. 



Text-ficfure 8. 



LEMUKS STOAT 



Different foi'iiis of transverse fissures and ridges on the dorsum of tlie tongue. 



Intermolar Elevation. 



In many animals the posterior part of the oral division of the 

 dorsum is elevated, thereby producing the posterior lobule or 

 intermolar elevation, so-called from its situation. In the Ornitho- 

 rhynchusit appears as a broad and expanded part of the dorsum, 

 and it bears two triangular processes, or lingual teeth, on its 

 anterior border. These are of value to the animal when it 

 catches its food while swimming in the water, for they direct the 

 insects into the cheek-pouches, whence they can be removed for 

 eating when the animal is at leisure. 



The Rodentia have well-developed elevations, which offer a 

 marked contrast to the low-lying anterior part of the dorsum. 

 Each of these divisions has a difierent function to perform. 

 The papillose anterior part is gustatory, whereas the posterior 

 lobule raises the food up to the molar teeth. 



The elevations difier in the abruptness in which they rise up 

 from the posterior end of the anterior division. 



The Lingual Papilloi. 



The lingual papillae are of three kinds — circumvallate, fungiform, 

 and conical. At the sides there are a number of fissures and 



