48 



Part III. — Twenty-fourth Annual Report 



II.— OBSERVATIONS ON THE OTOLITHS OF SOME 

 TELEOSTEAN FISHES. 



By Thomas Scott, LL.D., F.L.S., Mem. Soc. Zool. de France. 



(Plates I.-V.) 



Contents. 



PAGE. 



(1) Preliminary Remarks, 48 



(2) List of Fishes whose Otoliths are described, . . 52 



(3) Systematic description of the Otoliths, ... 53 



(4) Literature bearing on the Otoliths of Fishes, . . 80 



I. — Preliminary Remarks. 



Rather more than twenty-five years ago a portion of my leisure was 

 devoted to a study of the post-tertiary and surface geology of the Clyde 

 Valley. Consequently, the rich fossiliferous beds that were exposed 

 about that time in connection with the excavations for the James Watt 

 Wet Dock at Greenock were of special interest to me as well as to all 

 engaged in this study. It was about that time and in connection with 

 these researches that my attention was first directed to those curious 

 bodies known as the otoliths, or earstones of fishes. 



These studies had made me acquainted with the late Dr. David 

 Robertson, of Glasgow, and subsequently of Millport, whose name is so 

 intimately associated with the Marine Biological Station at the latter 

 place. This gentleman, who already possessed large collections of 

 natural history objects of various kinds, had among them an extensive 

 series of the otoliths of recent and known fishes, and these collections I 

 had the frequent privilege of inspecting. 



If I remember rightly, one of the reasons which induced Dr. Robertson 

 to make this collection of otoliths was that such objects were expected to 

 occur, or had already been noticed, in the fossiliferous clays then under 

 examination, and that, therefore, a familiarity with the recent forms might 

 help in identifying the kinds of fishes such fossil otoliths might belong to. 



With Dr. Robertson's assistance, always freely given to those engaged 

 in natural history pursuits, I soon became interested in these things. 

 Later on, when carrying out the work assigned to me by the Fishery Board 

 for Scotland, the food of fishes engaged my attention from time to time, 

 and in order to obtain the information desired it was necessary to 

 examine the stomachs of many of the fishes captured. As this 

 examination proceeded it became manifest that small fishes were often 

 captured by the larger specimens for food, as their remains sometimes 

 formed a considerable proportion of the contents of the stomachs examined. 

 Frequently, however, the otoliths or earstones were the only parts that 

 remained, or that were least affected by the action of the digestive fluid; 

 it was therefore obvious that a familiarity with the earstones of fishes 



