386 ]\rr. A. S. AYoodward on the 



little triangular plates of bone, much like those of Caturus 

 and Amia. In the description by Davis they are erroneously 

 ascribed to the jaws. just below and behind the head 

 (scarcely indicated in Davis's figure) there is a fragment of 

 the vertebral column clearly segmented into wedge-shsped 

 pleurocentra and hypocentra, and one of the latter displays 

 the short transverse process for the rib. The remainder of 

 the axis is obscured by pyrites as far as the middle of the 

 tail, where the overlajiping scales and crushing are also 

 detrimental to precise observation ; but the jileurocentral and 

 hypocentral ossifications in the hinder lialf of the tail are 

 either comparatively feeblfe or absent. Tlie upper caudal 

 lobe is atrophied as much as usual in the Protospondylic 

 fishes, and the caudal fin is quite normal. The supposed 

 " second series of intermediate bones to wiiich the fin-rays 

 are attached " (Davis) are merely the short unjointed bases of 

 the rays themselves. The fulcra on the upper caudal lobe 

 are also quite normal, the " five prong-like rootlets" depending 

 upon an error of interpretation. The well-preserved dorsal 

 fin seems to exhibit " smaller intermediate" rays between its 

 principal rays as the result of a little distortion by crushing; 

 the right and leit iialves of the rays in question are evideuily 

 somewhat displaced, and that of tiie right side becomes ex- 

 posed in posterior view just behind its fellow of the left side. 

 This often happens in fossilized fishes. The well-preserved 

 pelvic fill is interesting as showing for the first time in Osteo- 

 rachis the biserial character of its slender fulcra. There are 

 remains of large finely ornamented post-clavicular plates, and 

 the ciiaracteristic squamation is very well preserved over the 

 greater j)art of the trunk. 



EXPLANATION OF THE PLATES. 

 Platk vin. 



Fif). L CdluniK, sp. ; cranial roof, two thirds rat. size. — Oxford Clay ; 



Chri.-tian Malford, Wiltshire. [B. M. no. 2i)049.] 

 Fill. '2. Caiurus, sp. ; auterior end of cranium, two thirds nat. size. — 



Oxford Clay ; Peterboroufrh. [13. M. no. P. 690i>.] 

 Fi(j. 3. Cdtunti^, sp. ; head, right lateral aspect, two thirds nat. size. — 



Ibid. [B. iM. no. P. 6907.] 

 Flf/a. 4, 4 a. Caturus, sp. ; rijrht maxilla and palatine, outer and inferior 



aspects, two thirds uat. size. — Ibid. [P. M. no. P. (iylO.] 

 Fiq. 5. Catttru-'', sy. ; portion of gill-jxrches, two thirds uat. size. — Ibid. 



[P. M. no. P. Oi)06.] 



a.o., antorbital ; «./>., articular process of maxilla; «</., angular; br., 

 bianchiostegal rays ; c.o., circuniorbital ; d., dentary ; />*., fron- 

 tal; (/tt., gular jilate ; m.r., maxilla; tia, na.'-al ; occ, occipital 

 border ; jm., parietal ; pi., palatine ; jmu., premaxilla ; s.nijc., 



