1870. ] DR. J, E. GRAY ON THE DERMATEMYD. 715 
small, separate or united together into one plate. Intramarginal 
plates three on each side; the hinder in contact with the abdominal 
and femoral plates. Abdominal plate long. Axillary plate distinct. 
Tail conical, with a central ridge of spines on its upper surface, and 
some scattered tubercles on the sides converging towards the point. 
1. DERMATEMYS MAWII. 
Gular plates very small, separate. 
Dermatemys mawii, Gray, P. Z. 8. 1847, p. 56; Cat. Shield Rept. 
p. 49, t. xxi. 
Dermatemys mavei, Cope, Proc. Acad. Nat. Se. Phil. 1868, 
p- 120. 
Hab. South America (Mawe). B.M. 
2. DERMATEMYS SALVINII. 
The gular plates united into a single narrow triangular plate ; sides 
of the head and neck and upper surface of the feet olive, darker- 
spotted. In spirits. 
Dermatemys salvinii, Gray, P. Z. 8. 1864, p. 126 (animal). 
Hab. Guatemala (Salvin). B.M. 
I cannot see any other difference between these two species ex- 
cept the form and union of the gular plates. I believe this is per- 
manent ; but we require more specimens to establish the fact. The 
head and sides of the neck of Mr. Salvin’s specimen, in spirit, are 
pale olive with numerous darker spots ; aid the feet have some simi- 
lar spots. There is a little difference in the size of the intermar- 
ginal plates of the two specimens, but not more than shown on the 
two sides of Mawe’s original specimen. 
Mr. Cope describes his 7’. berardii thus :—* One gular, and an in- 
tergular behind it ; four or five inner marginals, the posterior in con- 
tact with femoral and abdominal; when only four, the median elon- 
gate ; vertebral scuta much longer than broad; no dorsal keel; ab- 
dominal scuta equal or broader than those adjoining.’ I suppose 
that this character is from a Mexican specimen. M. A. Duméril’s 
plate does not show any of them. The existence of any gular plate 
would indicate an irregularity in the specimen, or a structure which 
has not hitherto occurred to me, and, if normal, would remove the 
species to Hydraspide. 
2. CHLOREMYS. 
Head rather convex above. Thorax rather depressed, broad. 
Nuchal shield distinct and short. Vertebral plates keeled ; the first 
as broad as long; the second, third, and fourth broader than long ; 
the fifth rather narrowed in front. The gular plates small, united 
into one narrow triangular shield. The intramarginal plates three 
on each side; the hinder largest and not, or only slightly, in contact 
with the femoral plate. Axillary plate triangular. Inguinal band- 
like, transverse. Tail conical, very short, granular. 
