530 



PEOr. T. W. BEIDGE ON THE MESIAL 



The Mesial Fias of G-anoids .and Teleosts. By Professor 

 T. W. Bridge, D.Sc. (Communicated by Prof. Gr. B. Howes, 

 Sec. Linn. Soc.) 



[Eead 18th June, 1896.] 



(Plates XXI.-XXIII.) 



Page 



I. Introductory 530 



II. Descriptive 533 



Elasjiobranchix 533 



holocepiiala 534 



Ganoidbi 534 



Aeipensei-id£e 534 



Polyodont,id£e 536 



Amiidfe 537 



Lepidosteidse 540 



Polypteridse 541 



Teleostei 544 



Physostomi 544 



Ost eoglossidse 544 



Mnvgdnidse. 545 



Esocidse 545 



Cjprinid^ 547 



Salmonidse 550 



Siluridse 550 



Characinidse 556 



Clupeidse 557 



Gymnotidse 557 



Anacanthini 658 



Gadidfe 558 



Pleuronectidae 559 



Acanthoptbrygii 560 



BerycidjE 660 



Percidse 564 



Sparidae 566 



Scombridfe 567 



Carangidae 669 



SphyrsenidEe 569 



Cottidse 571 



Mugilidse 572 



Blenniidse 573 



Labridse 574 



FiatulariidsB 676 



CyclopteridEe 677 



Trachypteridie 577 



LopiioBRANCHir 578 



Syugnathidge 578 



Plectognathi 578 



Sclerodermi 578 



Gymnodontes 581 



III. Summary 584 



IV. Eeferences 600 



V. Explanation of Plates ; 



Reference letters 601 



I. INTEODUCTOJlY. 



There seems to be a certain amount of obscurity in the ordinary 

 text-book and other references to the structure and disposition of 

 the supporting skeletal elements of the mesial fins of Granoid and 

 Teleostean Pishes. These structures are usually referred to as 

 "ioterspinous bones or cartilages," and as a rule are described as 

 elongated, dagger-shaped bones which at their inner extremities 

 are intercalated between the vertebral neural or haemal spines, 

 and support distally the series of dermal fin-rays. It seems also 

 to have been tacitly assumed, if not actually so stated, that in 

 most instances each " interspinous " element is a simple unseg- 

 mented structure. Thus, Parker [1] in his paper on the skeleton 

 of Begalecus argenteus, after referring to the presence of a series 



