558 PROP. T. W. BRIDGE ON 'J'HE MESIAL 



tig. 19) consist of long, slender, rod-like proximal segments (p-s.), 

 eacb of which is slightly expanded and tipped with cartilage at its 

 distal end. There is no trace of mesial segments, or of postero- 

 superior processes to the proximal segments, and a series of 

 fibrous pads, interposed between the proximal segments and the 

 fin-rays, are all that represent the osseous or cartilaginous distal 

 segments of other Pishes. The radial elements have no articular 

 connexion with one another, and, except for a continuous liga- 

 mentous connexion between the distal extremities of their 

 proximal segments, are quite distinct. 



The fin-rays {f.r) correspond in number with their supporting 

 radial elements, and each is supported solely by a single element. 

 Their cleft basal extremities, which have irregular dentate edges 

 instead of smooth articular surfaces as in most other Teleosts, 

 embrace between them the fibrous representatives of the distal 

 radial segments. 



Akacanthini. 



G-ADID^. 



Gadus (Bglefinus. 



In this Gradoid there are three dorsal fins— an anterior, a 

 mesial, and a posterior, separated from one another by short 

 but distinct intervals. The anal fin is also divided into similarly 

 separated anterior and posterior divisions. 



Anterior dorsal fin. — Sixteen radial elements form the support- 

 ing skeleton of this section of the dorsal fin. All but the last 

 consist of a large well-ossified proximal segment with a well- 

 developed postero-superior process, and a small, cartilaginous, 

 nodular distal segment, which is embraced by the cleft base of its 

 dermal fin-ray. The last of the series consists of a small proximal 

 segment only, without a distal segment or a fin-ray. 



Mesial dorsal fin. — This fin is very similar to the anterior dorsal 

 but includes nineteen radial elements, each, including the last, 

 consisting of proximal and distal segments and supporting a 

 fin-ray. 



Posterior dorsal fin. — The posterior division of the dorsal fin 

 very closely resembles the mesial section. There are, however, 

 twenty radial elements and a corresponding number of fin- 

 rays. 



It may be noted that in each section of the dorsal fin the fin- 



