BEL0N0SX0MU3 CINCTUS, FROM THE CHALK OE SUSSEX. 145 



cess of the skull (ao) presents its usual aspect, and there is the 

 same excavation of the middle of the anterior extremity (ex) of 

 the cranial " box." The postorbital process seems to be buried in 

 the matrix, but the contour of tlie pustero-lateral angle of the skull 

 (j)/«) is quite normal, and the depression in the roof in advance of 

 the occiput is apparently of its accustomed proportions. The 

 pterygo-quadrate cartilage (ptq) is stout and narrow, with the large 

 pterygo-trabecular process ; the precise outlines of the mandibular 

 element are not seen. The left hyomandibular (hm) is perfect, in 

 position, of the ordinary shape and size ; and the large ceratohyal 

 (c7i) is shown in pieces upon both halves of the fossil, about two 

 thirds the length of the mandible. There are also apparently some 

 obscure remains of the well-developed labial cartilages. 



The dentition is not completely preserved, but the anterior teeth 

 of both the upper and lower jaw are exposed to view. Those near 

 the symphysis of the mandible are relatively high and slender 

 (fig. 3), while the opposing teeth attain but small dimensions 

 (fig. 2) ; more posteriorly, both above and below, the teeth begin 

 to exhibit the usual lateral elongation (fig. 4) characteristic of the 

 sides of the mouth. 



The minute dermal tubercles (fig. 5) are mostly of an oval form, 

 having the outer enamelled surface ornamented with longitudinal or 

 radiating ridges. They were probably scattered over almost the 

 entire trunk. The larger tubercles, like those occurring upon the 

 margins of the paired fins of the existing Squatina, are also oval in 

 shape, with a slightly crenulated margin (fig. 6). From the middle 

 of each there rises a large backwardly-directed spine, laterally com- 

 pressed, and well enamelled. 



On comparing the fish, thus fragmentarily indicated, with the 

 species of Squatina already satisfactorily known, it is readily distin- 

 guished by the great relative size of the spinous dermal tubercles. 

 No defences of this character have hitherto been observed in the 

 extinct forms, and those of the living species are considerably 

 smaller in proportion to the size of the fish. The anterior lower 

 teeth are also more slender than in the existing Squatina angelus. I 

 would therefore venture to designate the new English fossil jSquatina 

 Cranei, associating with it the name of my friend Edward Crane, 

 Esq., F.G.S., Chairman of the Brighton Museum Committee, as a 

 slight acknowledgment of the services he has rendered to the cause 

 of Palaeontology and the Institution over which he now presides. 



II. Belonostomxjs CINCTUS, Agass. (PI. YII. figs. 7-13.) 



The lower jaw of Belonostomus has already been, to some extent, 

 elucidated by the researches of Otto Reis*; but no specimen 

 hitherto described has revealed the precise characters of the denti- 

 tion, or the relations of the hindermost bones. Mr. Willett's fine 



* O. Eeis, "Uebei' Belonostomus, AsipidorhyncTius und ihre Beziehungen 

 zum lebenclen Le-pidosteus^^ Sitzb. math.-phys. 01. konigl.-bay. Akad. Wiss. 

 Miinchen, 1887, pp. 169-172, pi. i. fig. 4. 



