118 WEALDEN AND PURBBCK FOSSIL FISHES. 



region, the righl and left halves of each neura] arch are separate both from each 

 other and from the neural spine, which is comparatively short ; the ribs, which do 

 qoI reach the ventral border, arc very slender, but attached to rather stout 

 triangular ossifications abutting on the notochord. In the caudal region both the 

 neural and haemal arches are fused with their recurved spines, which are also 

 small. Beneath the upturned end of the notochord the haemal arches supporting 

 the caudal fin are much enlarged and thickened; and in'tlie upper caudal lobe 

 there are traces of a separate series of short rods below the f ulcral ridge-scales. 

 Fulcra are not clear on any of the fins except the caudal, but the rays and their 

 supports are well calcified. Six divided rays and one short simple anterior ray 

 are seen in one of the pelvic fins. Nine and eleven divided rays respectively can 

 be counted in the dorsal (fig. 8tt) and anal fins, besides a few short simple rays in 

 front, each ray (except perhaps anteriorly) being separated from its corresponding 

 support by a short intercalated rod, as in Amia. It may be added that there are 

 t races of ganoine on some of the rudimentary flank-scales. White granular 

 material, probably phosphatic, in the body-cavity may represent food. 



Horizon and Locality. — Lower Purbeck Beds: Teffont. Vale of Wardour, 

 Wiltshire. 



3. Pleuropholis crassicauda, Egerton. Plate XXIII, figs. 12, 13. 



1858. Pleuropholis crassicaudus, P. M. G. Egerton, Figs, and Descripts. Brit. Organic Remains 



(Mem. Geol. Surv.), dec. ix, no. 7, p. 3, pi. vii, fig. 2. 

 1895. Pleuropholis crassicaudata, A. S. Woodward, Catal. Foss. Fishes, Brit. Mns., pt. iii, p. 48-i, 



pi. xiv, fig. 5. 



Type. — Portion of fish; British Museum. 



Specific Characters. — As I', formosa, so far as known, but the trunk relatively 

 deeper, its maximum depth a little exceeding the length of the head with 

 opercular apparatus. 



Description of Specimens.— The type specimen in the P. B. Brodie Collection 

 (PI. XXIII, fig. 12) is too imperfect for specific determination, but it evidently 

 represents the same species as a more nearly complete specimen from the same 

 horizon and locality shown enlarged in PL XXIII, fig. 13. The latter may 

 therefore be used for the specific diagnosis, as above. 



The type specimen (PI. XXIII, fig. 12) seems to show the complete length of 



he head, with indications of the very large orbit, stained black, the short ethmoid 



and the narrow postorbitals traversed by a large slime-canal. The upper 



preoperculum, also with a conspicuous slime-canal, is distinct; and the 



rly complete operculum, abouf two-thirds as wide as deep, is seen to be 



lut marked with a slight vvaviness concentric with the lines of growth. 



