170 MR. NEWPORT ON THE NATURAL HISTORY, ANATOMY, 
its mode of development, and in its function, to true bone; and even as homologous with 
the external bony skeleton of Chelonian reptiles; the internal portions of which are similar 
in structure, as in office, to the internal processes of the tegument in the Articulata. 
But if, for the moment, in deference to the opinions of some physiologists, we were to 
discard this view of the nature of the tegument, and regard it simply as a dermal covering, 
we must still look upon it as but one structure, formed of layers of cells in different stages 
of growth; and not as composed of distinct tissues, epidermis, mucous layer, and corium, 
the definite limits of which it is perhaps impossible satisfactorily to indicate. 
When a very young Meloe (Tas. XX. fig. 1) is examined a few days after it has left the 
egg, its tegument affords a complete demonstration of celleeform structure. The whole tis- 
sue, if examined under a high power, is then seen to be composed of a uniform layer of 
irregularly hexagonal cells (fig. 4), which are almost equally distinct in the covering of the 
head itself as in that of the thoracic or the abdominal segments. In some parts of the tis- 
sue, as in the more transparent ones néar the spiracles (fig. 5), each cell is seen to contain 
a very delicate, granular, irregularly stellate nucleus, which I regard as corresponding to 
the cells seen by Platner in the tegument of the Silk-worm. Those cells which are on the 
surface of the body are of a somewhat quadrangular form, and they are arranged in a 
more linear direction than those which are deeper seated. Their nuclei are distinctly 
granulous, and occupy a very large proportion of the interior of the cells. This granular 
condition of the nuclei exists more especially in the cells of the thoracic segments, and 
closely resembles that in which, according to Mr. Tomes, true osseous matter is depo- 
sited in the Vertebrata. The largest of these cells measures about one two-thousandth of 
an inch in diameter. The cells in the tegument of the limbs are less uniform in structure 
than those of the body. On the femora they are slightly tuberculous, so that the limbs - 
are a little roughened on their surface; while on the tibial and tarsal ‘portions they are 
more elongated and are less distinct. This also is their condition in the antennee (fig. 6). 
The tegument has its own proper appendages in the form of hairs or imperfect spines 
(fig. 7). Hach of these spines projects from the surface of what, at first sight, appears to 
be a distinct opening in the external layer, but which is an enlarged and altered cell, 
the size of which, sometimes, is much greater than that of the other cells, and measures 
nearly one thousandth of an inch. It is circular, with a convex disc, bounded by a distinct 
margin, and surrounded by the proper cells of the external surface. In its centre is a 
slight elevation, from which passes out the minute hair or spine, perfectly smooth on its 
sides, and gradually diminishing in size from its base to its apex. When closely examined 
each spine is found to be hollow from one extremity to the other. From its central ori- 
gination, in a distinct structure homologous with that of the other cells of the tegument, 
I am induced to regard the spine, as, primarily, an excessive growth of the nucleus of a 
cell, everted and developed outwards as a single structure instead of being subdivided into 
nucleoli, or of secreting earthy matter, as in other instances, its cavity being continuous 
with a passage in the layers of cells beneath. 
Mes e oe a. d tegument is developed after the insect has left the egg, is 
dini ve mis a ns to that of its origination in the blastoderma. I have 
ascertain in the young Meloë. It commences in the formation of an 
