70 THE ASTEROLEPIS, 



plates, connected at the edges by flat squamous sutures, or, 

 as a joiner miglit perhaps say, glued together in bevelled 

 joints. And, in consequence of this arrangement, the same 

 plates which seem broad on the exterior surface appear com- 

 paratively narrow on the interior one, and vice versa : the 

 occipital plate {a), which, running from the nape along the 

 centre of the buckler, occupies so considerable a space on its 

 outer surface, exhibits inside a superficies reduced at least 

 one-half. Like nine-tenths of its contemporaries, the Astero- 

 lepis exhibits the little central plate between the eyes ; but 

 the eye-orbits, unlike those of the Coccosteus, and of all the 

 Dipterian genera, which were half-scooped out of the cranial 

 buckler, half-encircled by detached plates, were placed com- 

 pletely within the field of the buckler, — a circumstance in 

 which they resemble the eye orbits of the Pterichthys, and, 

 among existing fish, those of the sea-wolf. The character- 

 istic is also a distinctive one in Cuvier's second family of the 

 Acanthopterygii, — " the fishes with hard cheeks." A deep 

 line immediately over the eyes, which, however, indicated no 

 suture, but seems to have been merely ornamental, forms a 

 sort of rudely tatooed eyebrow ; the marginal lines parallel 

 to the lateral edges of the buckler were also mere tatooings ; 

 but all the others indicated joints which, though more or less 

 anchylosed, had a real existence. So flat was the surface, 

 that the edge of a ruler rests upon it, in my several speci- 

 mens, both lengthwise and across ; but it was traversed by 

 two flat ridges, which, stretching from the comers of the la- 

 tero-posterior, i.e. parietal plates (b, b), converged at the little 

 plate between the eyes ; while along the centre of the de- 

 pressed angle which they formed, a third ridge, equally flat 

 with the others, ran towards the same point of convergence 

 from the nape. The three ridges, when strongly relieved by 

 a slant light, resemble not inadequately an impression, on a 

 large scale, of the Queen's broad arrow. 



