LIASSIC FORMATIONS. 127 



tion at Bristol I counted 114 vertebrae; the terminal caudals showed in a greater degree 

 than usual the compressed character indicative of the vertical tegumentary fin. 



Parts of the carbonised integument are preserved on the slab of Lias on which lies 

 the above skeleton ; faint traces of integument lie above and beneath the deflected caudal 

 vertebrae ; a broad patch remains about four inches beyond the last preserved centrum, 

 though not the last of the series. This is the sole direct evidence I have as yet detected 

 of the tegumentary part of the tail-fin. Traces of the abdominal integument appear to 

 be smoother than in the similarly preserved skin figured in Buckland's, ' Bridgewater 

 Treatise.' 



If, as has been suggested (p. 86), the pectoral arch and fin relate to occasional 

 reptation on the sea-shore, it may be inferred, from the partial flattening of the articular 

 surfaces of the vertebral centrums, as well as from their proportions, in the present species, 

 characterised as it, also, is by more massive proportions of the pectoral arch and greater 

 relative size and strength of the fore paddles, that it was more littoral in its habits than 

 the majority of these marine Saurians. 



Saltford, near Bath, and the Penarth Beds (Rhcetic) of Glamorganshire are among 

 the localities of Ichthyosaurus latimanus. 



m. Ichthyosaurus brachyspondylus, Ow. PL XXXIII, figs. 3 — 6. 



This species is founded on vertebral characters, the centrums being shorter in 

 proportion to their height and breadth than in any other that has come under my 

 observation. 



In the abdominal centrum, the subject of figures 3 — 5, PL XXXIII, the breadth of 

 the articular terminal surface (ib., fig. 4) is 2 inches 11 lines; the vertical diameter is 

 3 inches, while the antero-posterior extent does not exceed 11 lines. In a more 

 posterior centrum (ib., fig. 6) in which the diapophysis (d) has descended to contact with 

 the parapophysis, the same proportions are preserved with slight diminution of size. In 

 a larger mid-dorsal centrum of this species which I examined in the private collection of 

 Mr. Rose, of Swaffham, the breadth was 3 inches 8 lines, the height 3 inches 9 lines, 

 but the length did not exceed 1 inch 5 lines. 



In a collection of fossils from Mid-Jurassic beds in the Province of Moscow, sub- 

 mitted to me by Col. Kiprianoff, in 1853, were centrums showing the same dimensional 

 characters, together with a low medial ridge dividing the under surface, which is, like- 

 wise, present in the British specimens. Col. Kiprianoff adopted the name, with my 

 determination, of his Ichthyosaurian specimens, other evidences of which have since 

 been detected and described in a valuable contribution to Russian palaeontology by 

 Prof. Trautschold. 1 



1 Trautschold (Prof. H.), * Erganzung zur Fauna des Russischen Jura,' 8vo, 1876, p. 5. 



