On the Caudal Fin of the Glupeidse, eye. 



531 



LXXIII. — On the Caudal Fin of the Glupeidse, and on the 

 Teleostean Urostyle. By C TATE Regan, M.A.. 



(Published by permission of the Trustees of the British Museum.) 



It is generally recognized that the Clupeidae are closely 

 related to the Elopidte, differing from them only in a few 

 features of specialization ; consequently a knowledge of the 

 structure of the latter family is essential to an understanding 

 of the anatomical features of the former. 



When I wrote an account of the skeleton of the caudal fin 

 of the Elopidse {supra, p. 354) it did not occur to me that 

 there could be any question as to the homologies of the 

 elements which I described with those of the Clupeidas ; 

 however, Mr. Whitehouse's note in the last number of the 

 ' Annals ' has shown me that I was mistaken, and I therefore 

 supplement my former paper with a description of the caudal 

 fin skeleton of the Clupeidoe, selecting for illustration that of 

 Chatoessus erebi. 



Fie- 1. 



..-"** 



Z:jV 



Skeleton of caudal fin of Chatoessus erebi. 



ep, epaxial basalia (epurals) ; u, uroueurals ; c, last centrum ; n, plate 

 representing neural arches of upturned centra ; hi/, hypurals. 



If the figure here given be compared with that of Flops 

 (p. 355) it will be seen that in both there is a series of three 

 epaxial basalia or epurals (ep) and that the hypurals (hy) 

 correspond well enough, the main difference being that in 



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