548 PEOr. T. W. BEID&E ON THE MESIAL 



(d.s.), is the proper fin-ray of tlie first radial element, hnt 

 although its bifid base clips the distal segment of that element, 

 it is mainly supported by the two laterally-placed facets on the 

 hinder margin of the distal extremity of the second proximal 

 segment. The twelfth fin-ray mainly is supported by the distal 

 segment of the nintb radial element (r.e.^). All the remaining 

 fin-rays are supported by a corresponding number of radial 

 elements, viz., by the second to the eighth inclusive. In most 

 instances not only does the cleft base of the fin-ray clip the 

 distal segment of its radial element but, in addition, articulates 

 by two basal condyles with the two facets on the anterior margin 

 of the distal end of the proximal segment of the next succeeding 

 element. 



As in some other Cyprinoids, there are two or three vestigial 

 radial elements which are represented only by proximal segmentsin 

 the form of small, thin, and somewhat irregularly shaped laminae 

 of bone, and are situated immediately anterior to the first ray- 

 bearing element. The vestigial elements undoubtedly indicate 

 the existence of a primitively longer dorsal fin than is present in 

 the adult, and it is quite possible that they may represent the 

 original fin-supports of those additional fin-rays which are sup- 

 ported by the first of tbe normal series of radial elements. 



Anal Jin. — This fin consists of seven radial elements and nine 

 fin-rays, and, on the whole, is very similar to the dorsal fin 

 (PI. XXI. fig. 13). In the series of radial elements, the presence 

 of a distinct mesial segment in addition to proximal and distal 

 segments is restricted to the fourth, fifth, and sixth. In front 

 of the fourth the elements arebisegmental, while the seventh has 

 only a proximal segment. The first element supports two fin- 

 rays in addition to partially supporting the third, which is its 

 proper ray. The fin-ray of the last radial element is firmly 

 attached to its predecessor, and is really supported by the distal 

 segment of the penultimate element. All the remaining fin-rays 

 are supported precisely as in the dorsal fin. 



Gyprinus carpio. 

 Dorsal fin. — Except for its greater length and the consequent 

 increase in the number of radial elements and fin-rays, which are 

 twenty-two and twenty-five respectivelj^ the dorsal fin of the 

 Onrp closely resembles that of the Barbel. The trisegmental 

 radial elements are the third to the twenty-first inclusive, the 



