ORGAN OF TASTE. 119 



in Siluridm, Characinidm, Cyprmidce and Gymnotidce. A 

 canal issues from the communication between vestibule and 

 its sac, and meeting that from the other side forms with it a 

 common sinus impar (Fig. 52,7^), lodged in the substance of the 

 basi-occipital ; this communicates on each side by a small 

 orifice with two subspherical atria, on the body of the atlas, 

 close to the foramen magnum. Each atrium is supported 

 externally by a small bone {m) ; a third larger bone (k) com- 

 pletes the communication with the anterior part of the air- 

 bladder. From the sinus impar a bifid canal penetrates into 

 the alisphenoids, in which it terminates. In Colitis and 

 several Loach-like Siluroids the small air-bladder consists of 

 two globular portions placed side by side, and wholly included 

 within two bullae, formed by the modified parapophyses of 

 the second and third vertebrae. The three ossicles on each side 

 are present, but concealed by the fore part of the osseous buUa. 



Organ of Taste. — Some fishes, especially vegetable feeders, 

 or those provided with broad molar-like teeth, masticate their 

 food ; and it may be observed in Carps and other Cyprinoid 

 fish, that this process of mastication frequently takes some 

 time. But the majority of fish swallow their food rapidly, 

 and without mastication, and therefore we may conclude that 

 the sense of taste cannot be acute. The tongue is often en- 

 tirely absent, and even when it exists in its most distinct state, 

 it consists merely of ligamentous or cellular substance, and 

 is never furnished with muscles capable of producing 'the 

 movements of extension or retraction as in most higher 

 Vertebrates. A peculiar organ on the roof of the palate of 

 Cyprinoids, is perhaps an organ adapted for perception of 

 this sense ; in these fishes the palate between and below the 

 upper pharyngeal bones is cushioned with a thick, soft con- 

 tractile substance, riclily supplied with nerves from the Nervi 

 vagus and glossopharyngeus. 



