28 BRITISH FOSSILS. 



developed, and greatly surpasses all the other fins. The scales also 

 present a certain resemblance to those of Ccelacanthus, in size as well 

 as in form. But, on the other hand, the structure of the rays is very 

 different ; their cutting edges are beset with spines, and they doubtless 

 served as protective weapons to the animal, while those of the Ccela- 

 canthus are smooth. The skeleton is strong, but I have not been able 

 to satisfy myself whether the bones are hollow or not." 



Maceopoma Mantellii, Agass. 



"...-... The head is very large ; it equals more than 

 one-fourth of the length of the body ; its bones are strong, and their sur- 

 face is finely dotted. In the specimen figured in Plate 65 a, the roof of 

 the cranium, the bones which surround the orbit, the jaws, a part of the 

 opercular apparatus, the branchial arches, and a part of the thoracic 

 girdle are readily distinguishable in their natural relations. 



" The lower jaw has a very irregular outline ; its dentary edge is 

 grooved in front, and descends towards its articulation with the 

 os quadratum. The pterygopalatine arch is very wide, especially 

 behind. It is the palatines and the vomer which carry the largest 

 teeth. On the other hand, the superior maxillary, which forms the edge 

 of the upper jaw, has none. 



" The fore part of the head [front] is concave, and rises as a rounded 

 projection above the orbit. The posterior suborbitar is a large osseous 

 plate, granular on its surface like the cranium ; the'anterior suborbitars 

 are elongated. The operculum has its posterior edge rounded. The 

 branchial arches are very large and strong, whilst the thoracic girdle is 

 proportionably weak. As in the pike, this arrangement is doubtless 

 calculated to facilitate the deglutition of a large prey. 



" The scales are large, and envelope the whole body in a thick 

 cuirass, which appears to extend very far on to the caudal, judging by 

 the impressions observable upon the lower lobe of the tail. The surface 

 of all the scales is granulated, and this granulation is so persistent as 

 to be recognizable when the scale is much worn. I have represented 

 in Plate 65 b, fig. 1, a portion of the body of a fish which I believe to 

 be the young of the same species, and whose scales are in so perfect a 

 state of preservation that their minute structure may be studied in 

 detail. They have for the most part a rhomboidal form, at least they 

 appear thus when superposed (as in nature). Isolated they present a 

 very different form, when the root of the scale is preserved, as in fig. 3, 

 Plate 65 b. Examined with a lens it is seen that the superficial 

 rugosities are produced by a quantity of little elongated tubercles, or 

 rather of small pointed cylinders, which cover all the visible part of 

 the scales. The largest and longest are in the middle of the scale ; 

 those at the sides are shorter and more slender : the covered part of the 

 scale is completely deprived of them ; it is smooth, and exhibits only 

 the lines of growth (Plate 65 b, fig. 3). For the rest there is no very 

 marked difference among the scales of different parts of the body. 



I have not succeeded in discovering any trace of the 



lateral line ; doubtless the superficial tubercles prevent the mucous 

 canals from being recognized. 



" The fins present peculiarities no less singular than those of 

 the scales. All the rays are stiff and very stout ; they do not 

 dichotomize, and are not jointed ; but on each side they are 

 beset with a series of strong spines, turned towards the extremity 

 of the ray. Their bases are divided into two branches, so as to form 

 a cleft which embraces the apex of the interspinous bone. At least, 



