FINS OP GANOIDS AND TELEOSTS. 545 



didtal segment it is clear that two elements contribute to tlie 

 support of eacli ray. 



Anal Jin. — The anal fin (fig. 8) is a facsimile of the dorsal fin 

 except for an increase in the number of radial elements and fin- 

 rays, there being twenty-six of the former and twenty-five of the 

 latter. 



MUE-ENID^. 



Conger conger. 

 Dorsal fin. — The extensive dorsal fin of this species resembles 

 that of Osteoglossum, and is equally primitive. All the radial 

 elements (PI. XXI. fig. 9) are similar in character, and all are tri- 

 segmental. The mesial segm.ents (m.s.) are well developed, and 

 although firmly united at one extremity to the proximal seg- 

 ments {p.s.), are nevertheless separated from the latter by well- 

 marked sutures. The relations and articulations of the various 

 segments of a radial element to one another and to those of 

 contiguous elements for mutual support are much the same as 

 in Osteoglossum. 



As in Amia and Lepidosteus, and as in most other Teleosts 

 ■with trisegmental radial elements, an interossicular ligament 

 (fig. 9, int. lig.) extends between and connects together the distal 

 aud mesial segments of successive radial elements. 



The fin-rays, as usual, are bifid at the base for the purpose of 

 clipping the distal radial segments by which they are supported. 

 Each of the basal arms of a fin-ray (fig. lOf.r.) is provided with a 

 peg-like projection or tubercle on its inner surface, and the two 

 tubercles of each ray fit into shallow pits or sockets on tbe 

 lateral surfaces of the distal segment (fig. 10, d.s. ; also fig. 9). 

 This method of connexion between fin-rays and the distal seg- 

 ments of their supporting radial elements will in future be referred 

 to as a " peg-and-socket " articulation. 



Anal fin. — The radial elements are precisely similar to those 

 of the dorsal fin. 



AnguiUa anguilla. 



In so far as the fin-supports are concerned, this species closely 

 resembles the preceding. 



ESOCIDJE. 



Esox lucius. 

 Dorsal fin. — This fin consists of about twenty-one soft fin-ravs, 

 supported by twenty radial elements (PI. XXI. fig. 11). The 



LINN. JOUEN. — ZOOLOGY, YOL. XXV. 44 



