248 
4. The relationship between the Air-bladder and Auditory organ in 
Amiurus. 
By Prof. R. Ramsay Wright, Toronto. 
eingeg. 31. Jan. 1884. 
Since the appearance of E. H. Weber's »De aure animalium 
aquatilium«, many observers have studied the »auditory ossicles« which 
effect a communication between the airbladder and the auditory appa- 
ratus of the Cyprinoids. Baudelot! has given a résumé of the earlier 
attempts to determine the morphology of these, and himself success- 
fully solved the problem in recognising the fusion of the 2"4 and 3" 
vertebrae. Later accounts? differ little from Baudelot’s as will be 
seen from the subjoined table, where, except in the case of Grass i’s 
interpretation of the Claustra, discrepancies are chiefly in nomencla- 
ture. 
Baudelot Nusbaum Grassi 
Claustrum . . Intercrural? I. Proc. Spin I. derived from Skull I. 
Stapes . . . . NeuralArch I. Neural Arch I. distal part Neural Arch I. 
Incus . . . . Neural Arch II. Neural Arch II. distal part Neural Arch II. 
Malleus . . . Haemal Arch III. Rib III. Proc. Trans. IT. 
With regard to Grassi’s interpretation of the Claustra I may 
state that their resemblance in Catostomus (the only Cyprinoid I have 
examined) to the undivided Proc.: Spin. II. and the relations which 
they bear to that bone are conclusive of the accuracy of the position 
taken by Baudelot and Nusbaum. 
I find no observations concerning the morphology of the anterior 
vertebrae in the Siluroids except Baudelot’s remark that »chez les 
Silures les osselets de Weber ont absolument la méme signification 
que chez les Cyprinsc. The object of the present note is to describe 
the condition of the parts in our commonest Siluroid Amiurus catus. 
The auditory ossicles. 
The Stapes is similar in shape to the same bone in S. glanis as 
figured by Weber, and has three processes 1) a globular articular 
cartilaginous process fitting into a cup on the dorsal surface of the body 
of the 1° vertebra, 2) an anterior spoon-shaped process which closes 
the Atrium sinus imparis laterally, and to the lateral surface of 
which the malleus is attached by means of the incus, and 3) a slender 
1 Comptes Rendus 1868. p. 330f. 
? Nusbaum, Zool. Anz. IV. p. 552 and (polish) in Kosmos. Lemberg 1883. 
Grassi, Morphol. Jahrb. VIII. p. 461. 
3 The spinous processes of several of the anterior vertebrae in the Cyprinoids 
are set on ,intercrurally‘: they are in part formed of elements comparable to the 
intercalary cartilages described by Goette in the Pike. 
