Thomas William Bridge. 



ix 



region has probably given rise to the ossicles, the homologies of which are 

 carefully considered. A well-reasoned discussion of their functions follows. 



It is a striking fact, as is pointed out by the authors, that " the presence of 

 a Weberian mechanism is characteristic of nearly all the dominant families 

 of fresh-water Teleostei " ; and it might be supposed that its possessors derive 

 " some exceptional advantage therefrom." What that advantage may be is 

 not perfectly certain, in the absence of sufficient experimental evidence. The 

 authors give weighty reasons for believing that the mechanism is not for the 

 appreciation of the small vibrations which are concerned in producing an 

 auditory stimulus, and conclude that it is probably to acquaint the fish, 

 tlu'ough the auditory organ, with the varying degrees of tension of the gaseous 

 contents of the air-bladder due to variations in the height of the superin- 

 cumbent column of water. It may be remarked that this manometer-like 

 function of the Weberian mechanism has recently been supported by Thilo, 

 who gives figures* showing the different positions assumed by the ossicles in a 

 Carp with the air-bladder respectively tense and flaccid. 



Of Bridge's other special Memoirs it is perhaps unnecessary to speak in 

 detail, since they can hardly appeal to any except Vertebrate Morphologists. 

 They include papers on the Skulls of Amia,\ PolypUrus, Lepidosireii, and 

 Osteoglossum, on the Osteology of Polyodon, on the Mesial Fins of Ganoids and 

 Teleosts, and on the Air-bladder and Auditory Organ of Notopterus. 



Bridge's latest work was his article on Fishes in vol. 7 of ' The Cambridge 

 Natural History,' and to this he devoted his best efforts. The writing of that 

 article gave him the opportunity of putting together and making available for 

 others his wide knowledge of the Morphology of Fishes, though other parts of 

 the subject were by no means neglected. Although some of his statements 

 have been criticised, the chapters contributed by Bridge to this volume are a 

 most valuable summary of a very difficult subject. As one of the editors of 

 the volume in question, the writer of this notice had many opportunities of 

 admiring Bridge's devotion to his work, the trouble he would take to avoid 

 carelessness or inaccuracy, and his keen desire to make his article as good as 

 possible, without thought of any other considerations. He was, perhaps, 

 unduly critical of his own performances, and was not satisfied to publish until 

 he had made himself certain that he had done everything in his power to 

 arrive at a correct result. This attitude of mind and the continued ill-health 

 from which he suffered were no doubt responsible for the fact that his list of 

 published papers is not a long one ; though, on the other hand, there is 

 probably nothing which he wrote that will not repay perusal. He was of a 

 reserved nature, and there were not many persons who were admitted to his 

 confidence. But those who knew him had a high respect for his thoroughness 

 and his disinterested singleness of purpose. He died, unmarried, on June 29, 

 1909. 



* ' Zool. Auzeiger,' vol. 32, 1908, p. 781. 



t A list of the more important contributions is given at the end of this notice. 



