THE DERMAL FIX-RAYS OF FISnES. 521 



Pig. 50. — Somewhat diagrammatic and enlar<red view of the distal region 

 of tliree lepidotriciiia, reacliing the edge of the anal fin, of Osteolepi^ 

 macrolepidotus. 



Fig. 51. — Enlarged view of tiie anterior edge of the base of the first dorsa. 

 fin of Osteolepis macrolepidotus, showing the transition between the 

 segments of the lepidotrichia and the body-scales. 



Fig. 52. — A touched-up enlarged photograph of a portion of the caudal fin 

 ofPalseouiscus sp. 



Fig. 53.— Enlarged view of the proximal region of the ventral caudal lobe 

 of tail fin of Palseoniscus Freieslebeni, showing how the dermal rays 

 pass below the body-scales. 



Fig. 54. — Enlarged view of three segments of the dermal ray at the 

 anterior edge of the same fin. 



Fig. 55a. — Outline of the tail of Amblypterus Blainvilli, shaded to 

 show the region represented in Fig. 55b. 



Fig. 55b. — Small portion of the caudal fin of the same, enlarged to show 

 the perfect transition between the body-scales and the joints of the lepido- 

 trichia. 



Fig. 56.— Small portion of the caudal fin of Diplopterus Agassizii, 

 enlarged to show the relation of the lepidotrichia of the ventral lobe to the 

 body-scales. 



Fig. 57. — Small portion of the second dorsal fin of Dipterus valen- 

 ciennesi, enlarged. One half represents the outer surface of the covering 

 scales, and the other half the impression left in the matrix by the scales of 

 the opposite side. 



Fig. 58. — Enlarged view of a portion of tlie lower edge of the anal fin of a 

 Dipterus valencienuesi, showing the dermal rays and overlying scales. 

 From a photograph touched up. 



PLATE 41. 



Fig. 59. — Portion of the lower half of the caudal fin of a salmon, Salmo 

 salar, dissected so as to show the relation of the hypural bones to the 

 dermal rays, two of which have been cut short at their proximal ends. 



Fig. 60.— Small piece of a lepidotrich from the pelvic fin of Polypterus, 

 superficial view. 



Fig, 61. — Small piece of a lepidotrich from the anal fin of Polypterus 

 bichir, showing the deep-lying canals in the bone, and the bone-cells. 



Fig. 62. — Transverse section through the distal region of the lei)idotrichia 

 of the caudal fin of Pholidopliorus sp. Cam. L. 4, oc. 3. 



VOL. 47, PART 4. NEW SERIES, L L 



