The Structure of Dinichthys 



167 



plates placed on top of it (ADL, PL) but overlaps them itself. The only overlapping 

 margins on the outside are on the point of the lower part (Text'figures 51, 52 and 53 Sp) 

 and the outside of the inner wing. 



The front margin of AL, from the upper angle of the plate {ua) runs downward in 

 the form of an arch. Then it makes a very sharp curve forward (d) and here defines the 

 lower part of the plate in a nearly straight line. The hind margin is much more angular. 



Text-figure 51. 

 The antero-lateral plate seen from the outside. 



A, upper part; a-b, line of section seen in inset; B, lower part; 

 ht, bottom of groove between B and C; C, hind wing; d, curv- 

 ing point of front margin; ha, hind angle; im, impression be- 

 tween B and C: la, lower angle; s, projection of unknown sig- 

 nificance; th, thickening between A, B and C; ua, upper angle; 

 X, curving point of hind ridge; y, groove between A, B and C, z, 

 front part of C. 



Text-figure 52. 

 The antero-lateral plate viewed from the inside. 



A, upper part; a, h, and c, curving points on limits between 

 ADL, AL and PDL; C, hind wing; ha, hind angle; la, lower 

 angle; s, projection of unknown use; ua, upper angle; x, curv- 

 ing point of hind ridge ; z, front part of C. 



From the upper point it runs obliquely downwards in an uneven line to the hind angle 

 (ha) of the plate, from this point down to the lower angle (la), and on forward, forming 

 the lower margin of the lower part of AL. The part around the lower angle and along 

 the lower margin is relatively thin and shows a rough surface with many small impres- 

 sions. It is probable that some ligaments or muscles have been attached to these parts. 

 Immediately above the lower angle a little projection (5) of unknown significance is 

 generally found. 



