79 



On Fishes' Tails. 



By E. T. Newton, F.G.S.* 



Read March 21, 1882, 



Plate III. 



Part I. 



DESCRIPTION OF THE TAIL OF A YOUNG SPRAT, AND COMPARISON 



WITH OTHER RECENT FORMS. 



Some years ago, when studying the osteology of the common Sprat 

 (Harenga sprattusj I was much interested in the structure of the 

 tail, which seemed tome to present peculiarities worthy of a careful 

 investigation. One of the youngest examples which could be ob- 

 tained was prepared and mounted in glycerine jelly. Drawings 

 of this having been carefully made, it was put on one side in the 

 hope of obtaining still younger specimens, so that, if possible, its 

 development might be worked out, and compared with the various 

 early stages of the Gasterosteus, the development of which had 

 been so ably investigated by Prof. Huxley. f Unfortunately I 

 have not been able to get any smaller and younger specimens ; 

 but it seemed to me that possibly the description of this preparation, 

 and its comparison with other forms, might be sufficiently interesting 

 to justify my bringing it before the Club. 



Before commencing this description it will be well just to say a 

 few words on the forms of fishes' tails generally, for the terms which 

 have been used with regard to them do not appear to be clearly ap- 

 prehended by many persons. 



In so far as the external form of fishes' tails are concerned 

 they present two main types, namely, — those in which the fleshy por- 

 tion of the body is continued upwards to a greater or less extent 



* At a time when microscopical subjects are so freely admitted to the 

 publications of other than microscopical societies, no apology is necessary 

 for bringing before the Quekett Club a paper like the present, which, al- 

 though treating of macroscopic matters, is founded upon microscopic 

 work. 



t " Quart. Journ. Micro. Sci." vol., vn., p. 33, 1859, 



