^^^' 55'] AiriA FEOIE THE ISLE OF WIGHT. 5 



deficiency (see PI. I, figs. ] 5-1 6). There is no proper symphysis, but 

 the anterior extremity is a thin edge, which curves downward and 

 backward from the dentary margin, and, continuing almost parallel 

 with the latter for some little distance, somewhat suddenly descends, 

 there being thus a rapid increase in the depth of the hinder half of 

 the bone. The external rugosity continues to the anterior end, and 

 in all the specimens there are a few of the rugose apertures near 

 the curved extremity. The groove on the inner surface is a broad 

 flattened space that widens anteriorly (see PI. I, fig. 15 a). 



The clavicle and preoperculum have rugose sculpturing on 

 their outer surfaces. The parasphenoid (PI. I, fig. 5) has a 

 large flattened area on its oral aspect, covered with minute denticles ; 

 and fragments of several thin bony plates, evidently from the oral 

 cavity, are similarly armed. 



Specimen 11. (PI. I, figs. 6-14.) 



A second specimen, which includes several parts of one fish, and 

 is to be referred to the present species, was obtained by Mr. Colenutt 

 from Bed 5 of his section of the Osborne Series at King's Quay ^ 

 (Isle of Wight). These bones were all found near together, and 

 there is but little doubt as to their pertaining to one fish ; they 

 include fifteen vertebrse, a pair of premaxillae, part of a dentary 

 bone, several pieces with ornamented surfaces (evidently belonging 

 to the skull and opercular apparatus), and a single scale which, 

 though imperfect, is most valuable as further evidence of the 

 afSnities of these remains. This fish was somewhat smaller than 

 specimen ISo. I above described, but, in so far as comparison can 

 be made, agrees with it in all essential particulars. 



Vertebrae. — All the vertebrae are somewhat asymmetrical (PI. I, 

 figs. 6-10) ; seven belong to the anterior part of the column, and in 

 form agree very closely with those of specimen No. I. Only the 

 bases of the transverse processes are preserved, but these suffice 

 to show the relative positions of the vertebrae in the series. The 

 centrum which bears the processes highest up on the sides has an 

 almost quadrate terminal face, and must have been very near the 

 skull. The third vertebra of this series agrees as closely as may be 

 with the first vertebra in the previous specimen, but it is not quite 

 so pointed below. 



The variations in the proportion of length, height, and width of 

 these vertebrae are shown by the following measurements of some of 

 them : — 



Measurements of Vertebrae in Millimetres. 



Ill VII IX XI XII XIII 



Length 8 9 10 9-5 8-5 5 



Height 18 18 17 18 16 14 



Width 25 24 21 18-5 15 14 



In ^0, XI the height and width are equal, and the processes 

 1 aeoL Mag, 1888, p. 358. 



