38 Mr Taylor on the Respiratory Organs and Air-bladder 



whom they were discovered, in all the osseous fishes, in the vi- 

 cinity of the anterior or cervical vertebra?. — (Blunien bach's Com- 

 parative Anatomy, p. 285.) They exist in the different species of 

 the genera Silurus, Pimelodus, and Cyprinus, I have had an 

 opportunity of examining ; but are apparently wanting in the 

 genera Ophiocephalus, Coins and Trichopodus : and also in the 

 Bola Pama, Mystus Chetala, and Clwpanadon Ilisha, in which 

 species their place is supplied by a direct connection between the 

 two organs. The bone corresponding to the malleus is consider- 

 ably larger than either of the other two, and is uniformly si- 

 tuate at the anterior extremity of the air-bladder, extending 

 along the side of the spine to opposite the first vertebra. In 

 the Silurus Boalis its anterior half is long, flat, and of a tri- 

 angular shape, terminating in a blunt point, while the posterior 

 portion is crescentic, having below a scabrous surface, to which 

 the external coat of the air-bladder is firmly attached. By 

 means of a short styloid process, projecting from the side of the 

 latter portion, and received into a pit on the body of one of 

 the vertebra?, this bone enjoys a limited degree of lateral motion, 

 by which its apex can be made to approach or recede from the 

 spine. The incus, which is of a short cylindrical shape, is 

 placed between the apex of the malleus, and the bone corre- 

 sponding to the stapes, and at a right angle with the former : and 

 is attached to each of these bones by a short round thick ten- 

 don, in the centre of which it presents the appearance of being 

 imbedded. The stapes may be described as consisting of two 

 parts : one is a thin hollow portion, of an oval figure, somewhat 

 resembling the bowl of a spoon, having the tendon of the incus 

 attached to its convex side ; the other consists of a small round 

 knob, with a minute spicula projecting from it, and is joined by 

 a neck to the small end of the first portion. It is situate in a 

 large foramen in the first vertebra, and forms one of the sides 

 of a small chamber communicating with the cavity of the cra- 

 nium. This chamber lies immediately behind the cavity con- 

 taining the sac and ossicula, or calcareous bodies of the inter- 

 nal ear ; and within the canal of the first vertebra, its roof 

 being composed of a strong tendinous membrane, that supports 

 the medulla spinalis above. The oval portion of the stapes, 

 with its concave side presented towards the interior of the 

 chamber, is loosely connected by a membrane, to the edge of 



