628 PROF, H. G. SEELEY ON THE DINOSAURIA OF 
istic Dinosaurian convexity on the middle of the dorsal surface, but 
appears to be less concave than usual on the ventral aspect. Some 
doubt may well attach to the association of this bone with the ver- 
tebral column. 
There are twelve subovate pieces of dermal armour reputed asso- 
ciated with the skeleton. They vary from 24 to 34 inches in length, 
are about 2 inches wide, and have a strong elevated angular crest 
and fold running down the length of the plates, which have the 
lateral halvesa little concave. The margins are thin and show no signs 
of overlapping, except at the posterior ends ; and the external surface 
is roughened, with an irregular pitted appearance, similar to that 
seen in Acanthopholis and Scelidosawrus. The dermal surface is 
usually smooth and concave; but one symmetrical plate has the 
under surface deeply excavated, evidently for a muscle, and may 
therefore be inferred to be one placed over the neural spine of a 
vertebra; it is, however, in a slightly different state of minerali- 
zation, and possibly may not belong to the series. It must remain 
for the present an unsettled question whether Syngonosaurus was 
really armoured, though the probabilities lean in that direction. 
The only existing reptiles in which dermal armour of the pattern 
found among the Dinosaurs is met with are the Chelonians ; and 
in that order, both on the limbs and tail, dermal bones, covered 
with a horny sheath, are found, which differ from those of Dinosaurs 
chiefly in size. 
Parr VI. 
On the Dorsal and Caudal Vertebre of Acanthopholis stereocercus, 
Seeley, a Dinosaur from the Cambridge Greensand, preserved in 
the Woodwardian Museum of the University of Cambridge ; with 
some notice of a second species of Anoplosaurus collected with these 
remains. 
Among the smaller series of Dinosaurian bones collected for the 
Woodwardian Museum by Mr. W. Farren, is a collection of twelve 
vertebre and a fragment of a dermal spine, which were catalogued 
in my Index to Aves, Ornith. and Rept. 1869, pp. xvii and 24, as 
Acanthopholis stereocercus. Looking at the specimens anew, I have 
no doubt that the remains are not all referable to one species. The 
first, which is in bad preservation, is a cervical ; it has, apparently, 
got into the washing-mill and become worn. It is so far similar 
to Anoplosaurus as to suggest that it really belongs to the neck of 
a second species of that genus. The next two are dorsal; then 
follows‘a postsacral of remarkable form, which is succeeded by an 
early caudal. The next three caudal vertebre I do not now regard 
as pertaining to the same species, and separate them as belonging 
to a second and undescribed species of Anoplosawrus. They 
want the median groove on the base of the centrum, which is 
characteristic of the caudals of Acanthopholis, and in all essential 
characters they have the general facies of caudal vertebree of Ano- 
plosawrus ; but differ from the species already described in the ver- 
