PART 2.] 
Stoliczka, on Pangshura tecta. 
37 
about equal to, or a little shorter than, the sternum, and slightly emarginated; posteriorly 
it is obtusely rounded, and at the marginal shields more or less distinctly serrated. 
In the specimen figured on Plate I,—which was discovered by Mr. W. Theobald 
at Moar Domar in the Nerbudda valley,—the carapace agrees in every respect with that of 
the recent species, as will he shown by giving the necessary details of its structure. To 
facilitate a careful comparison, I have also given a drawing of one-half of the dorsal and 
ventral views of the carapace of a small specimen, procured living in the neighbourhood 
of Calcutta. These drawings are intended to illustrate not only the epidermoid but also the 
osseous shields. Proper attention is seldom given to the latter in zoological works, although 
in palaeontological researches they are of greater importance than the former. 
The fossil figured is not perfect, the posterior portion of the carapace not having been 
found; hut the rest of the shell is quite sufficiently preserved to admit of careful comparison 
for specific, identification. The general form of this fossil is, as already stated, exactly the 
same as that of recent specimens. 
Epidermoid plates .—-The nuchal shield is very small, narrower anteriorly than posteriorly 
All the five vertebrals are obtusely curinated in the middle, and the first three become 
successively more and more elevated at the posterior end. The first vertebral is pentagonal 
with an obtuse projecting angle in front, slightly emarginated at the sides, narrow and 
truncate behind. The second vertebral is about the same size as the first, also pentagonal 
truncate at both ends, considerably narrower posteriorly than anteriorly, laterally' 
at one-third of the length from the front edge, widest and angular. The third vertebral 
is the smallest, but the highest of all, pentagonal, truncate in front, angxdar at the 
sides, after which considerably produced posteriorly, becoming gradually narrower and 
terminating with an obtuse point. The fourth vertebral is hell shaped, very much 
prolonged, joining the third with an obtuse point, then becoming gradually wider until 
it reaches about three-fifths of its length, after which it narrows again, tenninatino- with a 
truncate side, about one-half of the greatest width of the shield. Of the fifth vertebral only 
the anterior portion is preserved, showing it to be truncate in front and quickly widenin'^ 
posteriorly. The sides were probably obtusely pointed and the posterior termination truncate 
broader than the anterior, as in recent specimens. In these the sides of the fifth vertebral 
are sometimes pointed, sometimes distinctly truncated. Costal or lateral plates are five all 
being transversally elongated and of a more or less irregular pentagonal shape. They 
entirely agree with those of living specimens, as is equally the case with the marginal shields 
which are eleven in number on either side. The serration of the posterior marginal shields 
remains to he properly recorded if better preserved specimens should be discovered, for neither 
is it distinctly traceable in the figure given by Dr. Murchison in Falconer’s Pal. Memoirs. 
On the ventral side we have first to notice a pair of small, triangular, posteriorly pointed 
gular shields. To these follows a pair of larger, subquadrangular post-gulars ; then a pair of 
rather high pectorals, next to which are the abdominals, being the largest, and then the other 
shields of normal size. The axillaries are comparatively .small, posteriorly pointed, the 
inguinals large anteriorly, on the external side obliquely truncate. The longitudinal rid°-e 
which connects each axillary with its corresponding inguinal is very distinct, sharp and 
slightly longer than in most recent specimens. The plastrum is distinctly concave, probably 
a little more so than in male specimens, as usually met with about Calcutta. 
Osseous plates .—The distribution of the osseous plates, as is well known, does not a»ree 
with that of the epidermoid shields. There is a very large nuchal plate and a very small 
caudal, the latter not being preserved in our specimen. There are ten small vertebrals, the 
last (the largest) not being seen in the fossil, but the other nine perfectly agree in their 
relative proportions and in their relations to the epidermoid shield with those of live 
specimens. The costal shields are eight; the first is the broadest, with reference to the 
longitudinal diameter of the carapace; all the others are very narrow. The number of 
marginals is eleven on each side. 
On the plastrum we have a pair of subquadrangular gular shields, to which follows a 
pair of very large pectorals, these four shields enclosing in the middle a single, suboval post- 
gular; there is besides a pair of very large abdominals and one pair of smaller anals. The 
axials and inguinals are not separated from the pectorals and abdominals respectively. 
No portions of the internal skeleton, as the extremities, &e., have been found preserved. 
