298 MISS EDITH E. BAMFORD OX THE 



plate in the mesopterygium encloses numerous fat-cells, and 

 branches from the bloofl-vessels passing through the foi-amina 

 ramify among them. The left pectoral fin of a specimen 24 cm. 

 long had no indications of an ossified plate, the right pectoral fin 

 being normal. Ossification of the mesopterygium is not always 

 confined to the large ossified plate : I have often seen bone-cells 

 in the proximal cartilage between the converging propterygium 

 and metapterygium, and also occasionally veiy small ossified 

 plates similar to the large one ; calcification of the mesopterygial 

 cai'tilage in specimens measuring from 21 to 30 cm. is frequent. 



The metaptevygium showed little variation : one adult Poly- 

 ptertts had a forked metapterygium (text-fig. 58A). 



Yariations were frequent in the distal epiphyses of the pro- 

 pterygium. Klaatsch describes the fin of a young Calamoichthys 



Text-fig. 59. 



Propterygium of fin of Folypterus, with ossified outgrowth and cartilaginous 

 epiphj'sis in the position of the small cartilage generally found at this 

 place. 



18 cm. long, in which the epiphysis is not separated from the 

 mesopterygium, and one 25 cm. long, in which it is separated. 

 He says he has never found this vinion in a Polypterus fin. 

 Wiedersheim's illustration of a Polyptertts fin shows a distal 

 cartilaginous epiphysis, and succeeding it a piece of cartilage 

 continuous with the mesopterygivim. I have very often found 

 the epiphysis of the Polypterus fin continuous with the meso- 

 pterygium in specimens varying from 13 to 43 cm. in length 

 (text-fig. 58, A, B), but I have never seen a distal epiphysis suc- 

 ceeded by cartilage continuous with the mesopterygium as shown 

 by Wiedersheim. The propterygium in a few cases showed 

 indications of a forking of the ossified distal end. 



