10 Mr. A. S. Woodward on some 



(PI. I. fig. 1, p. op.) it is shattered by fracture in front, but it 

 is well preserved at the upper end ; and in this fossil, as also 

 in no. 2, there is shown interposed between it and the 

 squamosal a small apparently nearly square plate [z], which 

 is tuberculated as usual. The preoperculum thus does not 

 extend upwards quite so far as the operculum, which seems 

 to touch the hinder angle of the cranial roof; but its great 

 expanded inferior portion reaches considerably further down- 

 wards on the cheek than the tapering lower end of the latter 

 element. Below the preoperculum in no. 1 there are remains 

 of two slender plates having the appearance of brancliiostegal 

 rays, the upper of considerable size, the lower very small and 

 delicate. The first is also seen in nos. 2 and 23, and on the 

 external face it is always in part tuberculated. The space 

 between tlie mandibular rami (PI. III. fig. 2) is completely 

 covered with very small and delicate polygonal tessellated 

 plates (i.), marked with a tubercular ornament as coarse as 

 that of the other bones. 



Appendicular Skeleton. 



The post-temporal bone and supraclavicle are not recog- 

 nizable. There is reason to believe that neither of them was 

 exposed on the tuberculated exterior of the fish, for in no. 1 

 the expanded upper end of the first dorso- ventral series of 

 flank-scales is shown to curve forwards and to be directly 

 overlapped by the small supratemporals. The same arrange- 

 ment is also suggested by no. 2, where the foremost scales 

 are displaced and exhibit the comparatively fine tubercles of 

 their hidden front margin. The clavicle is relatively small, 

 and this element of the left side is detached in no. 24. Its 

 exposed portion (PI. II. fig. 6) is restricted and narrow, orna- 

 mented with tubercles only on its short inferior limb, while 

 its long fibrous upper limb is considerably thickened. There 

 is no laminar expansion of the bone bent inwards at its ante- 

 rior border. The coraco-scapular attachment is shown on the 

 inner face (PI. II. fig. 6 a), but neither coracoid, scapula, nor 

 basals are preserved, only the unjointed bases of the fin-rays 

 in one specimen. 



The pelvic fins are present, but quite small and insignifi- 

 cant. The best-preserved example in no. 1 exhibits only five 

 rays, which are rather stout and soon become very closely 

 divided and articulated at a short distance above the base. 

 Nothing is known of the basal pelvic elements. 



Of the median fins only a fragment at the origin of the 

 caudal is preserved in no. 2, This is identifiable on com- 



