SIWALIK AND NARBADA CHELONIA. 
37—191 
3rd vertebral plate includes a vertebral bony scute situated between two other scutes 
respectively impressed by the fore-and-aft boundaries of the plate : in the present 
specimen the two vertebral scutes so marked are contiguous, and of an extremely 
elongated form. This important difference clearly indicates the specific distinctness 
of the present specimen from B. falconeri ; and also from the living B. thurgi and B. 
baska, in which the same feature exists. The writer has been unable to observe the 
relations of the vertebral bony scutes to the 3rd vertebral plate in all the living 
species, but he finds that in B. Imchuga^ B. trivUtatiis, and B. dhongoJca their relations 
are the same as in the fossil now under consideration, and it may, therefore, be 
concluded that this condition prevails in all the species having a long 4th vertebral 
plate (section a of group A) ; while the opposite condition is known to obtain in 
those species having a nuchal plate and a short 4th vertebral (section J), and not 
improbably also occurs in group B. 
The specimen under consideration also differs from B. falconeri, in the form of 
the nuchal and 1st vertebral plates, as well as in the profile of the shell, the absence 
of a vertebral keel, and of distinct areolae on the carapace. 
The carapace is strongly vaulted, although to a somewhat smaller extent than in 
the last species ; the highest point of the shell is situated near the middle ; and in a 
profile view (pi. XXIV. fig. 5) the ascent from the anterior border of the carapace to 
this point is very gradual. The nuchal plate forms a broad triangle : the 1st 
vertebral plate is nearly square, and as long anteriorly as posteriorly ; the 2nd is 
longer than either the 1st or 3rd, and is also nearly square ; the 3rd is broader than 
long ; the 4th is much narrower than the 3rd ; its posterior boundary is unfortunately 
not shown, but judging from the shape of the anterior portion, and the relation of 
the 3rd plate to the underlying scutes it is evident that it was of the elongated type 
of B. kachuga and B. dhongoJca. The plastron is rounded, the sutures separating the 
postgulars and pectorals forming a very obtuse angle ; both the postgulars and 
abdominals are longer than the pectorals ; and the inguinal incisions are separated 
by a wider interval than are the axillary. There is no trace of any vertebral keel. 
Distinctness and affinities. — The specimen under consideration is distinguished 
from the living species of group B by the presence of a nuchal plate ; and, as 
mentioned above, from section b of group A by the relations of the 3rd vertebral 
plate to the underlying scutes, as well as by the elongated 4th vertebral plate. In 
section a of the latter group the present form is distinguished from B. dhongoJca and 
B. trivittatus by the obtuse angle formed by the suture between the postgular and 
pectoral plates ; and there accordingly only remain B. JcacJmga and B. ellioti with 
which it can have any affinity. As far as concerns the latter it can only be said that 
the young is characterized by the extreme breadth of the 2nd and 3rd vertebrals, 
which are not characters found either in the specimen under consideration or in the 
adult of B. JcacJmga. The present form agrees with the latter species in the general 
form of the nuchal and vertebral plates, and of the profile of the shell ; it also 
1 The sioecimen in the British Museum showing this belongs to the so-called B. fuscus. 
J 
