78 SUPPLEMENT ON 



osseous or membranous fraena, surrounded by semi-circular 

 canals, and the cavity in the face of the cranium, above 

 the basilary bone, containing the bag commonly appended to 

 the vestibulum, filled with gelatinous liquid. In this, and in 

 the vestibulum, there are usually several bonelets, or rather 

 calcareous, or testaceous nodules, in osseous fishes, and re- 

 sembling starch in chondropterygians, of such determined 

 forms that the osseous species might be readily distinguished 

 from each other by this criterion alone. Several genera, such 

 as carp, cat-fish, loches, &c. have received a special appara- 

 tus, by which anatomists have surmised that the deficient 

 organs of the ear are in a great measure supplied ; but these 

 form exceptions, and it may still be asserted, that fishes have 

 not hearing sufficiently delicate to distinguish varieties of into- 

 nation. That sound produces concussions acting powerfully 

 upon them without the perception of modulation is evident, 

 and hence they are scared by thunder, and fishermen practise 

 silence while engaged in casting their net ; but still all that 

 the hearing of even the best endowed species can claim, is 

 that a few of them can be called together by a bell, a whistle, 

 or, as the ancients assert, can be made to know their names. 



TJie nostrils are not constructed in such a manner as to 

 allow either air or water to traverse them in respiration. 

 They consist of two excavations, formed towards the point of 

 the snout, lined with a pituitary membrane, disposed in very 

 regular folds ; they are oblong, oval, or round, placed at the 

 point of the head, on the sides, and sometimes on the upper 

 surface of it. In the lamprey they are near the summit of the 

 head, and unite to form a single opening ; in squali and rays 

 they are on the inferior side, near the angles of the mouth. 

 Most if not all osseous fishes, have what is called double 

 nostrils ; that is, two openings on each side of the head, 

 but the two form in reality but one cavity ; the anterior 

 orifice is often tubular, those of the angler are in the 



