390 Proceedings of the 



in the species before us. On removal of one side of the neural 

 arch of the conjoined vertebrae, the upper surface of the body 

 is seen to be divided by two transverse elevations into three 

 equal parts of the same length as the bodies of the other ver- 

 tebrae, and the third and fourth are not more distinctly sepa- 

 rated than the second and third. Moreover, there are seen 

 three pairs of foramina for nerves, the first passing out above 

 the spring process, the second above the transverse process of 

 the third vertebra, and the third close to the posterior margin 

 of the fourth vertebra. These circumstances leave no room 

 to doubt that we have really to do with three vertebrae united 

 together. The transverse processes of the fifth and sixth 

 vertebrae arise from the junction of the neural arch and body ; 

 those behind arise from the sides of the bodies, each pair on 

 a lower level than the pair in front. 



In connection with the three first vertebrae are three pairs 

 of little bones, or processes, of the description called Weber's 

 apparatus. The bone belonging to the first vertebra — the 

 stapes — is situated behind and below its neurapophysis. It 

 consists of a linear portion, similar in size and shape to the 

 neurapophysis, and of another portion, oval and hollowed on 

 the inner aspect, and lying at right angles to the lower ex- 

 tremity of the first portion, directed forwards. Bilharz, as 

 above mentioned, describes the linear part as a separate bone, 

 but since he represents them united, in his sketch of the sepa- 

 rate bones ; and since the stapes of Silurus glanis repre- 

 sented by Weber* is exactly the same shape as that of Ma- 

 lapterurus, if we include the linear part ; and since, in the 

 species before us, I can see no symptom of the portions being 

 separable ; I am inclined to think that Bilharz must be mis- 

 taken in describing them as distinct bones. The bone in 

 connection with the second vertebra — the malleus — is con- 

 siderably larger. It lies along the side of the body of the 

 vertebra, and is straight anteriorly, but curved downwards 

 and inwards posteriorly over the lateral foramen in the body 

 of the vertebra. At its centre it is attached by a very slender 

 thread of bone to the upper part of the body of the vertebra, 

 so as to admit of considerable motion. In the Silurus glanis 



* Weber, De aure et auditu. 



