DR. W. C. M'INTOSH ON THE HAIRS OF CARCINUS MANAS. 93 
Out of the horny insertion a range of strong palisades arises, and from the extremities of 
these proceed the minutely-bristled hairs. The posterior part of the ridges (Pl. XX. 
fig. 11) presents areas of finely dotted cells or areolæ, above which in the figure there is 
a curious portion with small groups of processes or spikes covering it in a somewhat 
regular manner. In this figure the origin of the hairs from the firm base of the horny 
ridge appears to the right; the dark gs odd below is the calcareo-horny matrix from 
which the latter springs. 
From behind forwards, the general arrangement of the hairs of the 
region to the outer side of the ridges, c c, in fig. 10, and the right one 
of which is indicated in fig. 11, is as follows:—The strongly-bristled 
internal ridge, c, runs pretty evenly to its anterior términation, where 
the bristles diminish in size and disappear. Sometimes before they 
do so, however, a blank occurs; and this occasionally presents a short 
pale tooth or two, as if the regenerating process had commenced.. Slightly exterior to 
the anterior termination of the row is a dark isolated tuft, d, which, when carefully 
examined, is found to consist of a peculiar pointed process, of the hardness of the teeth, 
springing from a dense group of the ordinary hairs, and bearing in addition many of the 
same on its sides (Pl. XIX. fig. 17). In the soft Crab it is generally coated with hairs 
to the tip, but in the ordinary condition it is as figured. The surface of the membrane 
in front of this is left bare for some distance. 
From within outwards in the same portion are, first, the inner edge of Fig. 11. 
the horny ridge which by-and-by bears hairs; secondly, to the exterior 
of this comes another row of hairs, e, fig. 11, which, however, are neither 
so long nor so regularly set as those of the internal one; they seem 
rather a closer matting of the numerous hairs which now thickly cover 
the membrane; thirdly, external to both of the foregoing is a tolerably 
abundant supply of hairs of the same calibre, but shorter and frequently 
broken, and whose roots end in a cell-like bulb; lastly, the membrane from which the 
latter spring becomes paler, and hairs are met with having the gland-like cells mingled 
with them, as shown in Pl. XX. fig. 6, and which extend over a considerable area both 
amidst and beyond the hairs. The hairs, dwindling into small points, cease. 
The central portion, f, fig. 10, between the ridges, is composed alike of horny and mem- 
branous texture, and seems to have the following arrangement :—In front and laterally it 
is covered by an immense number of those gland-like bodies, which appear, in those 
whose structure is best discernible, to consist of a minute tuft of processes or microscopic 
spikes, springing from the membrane by a dense, granular root, often in a brush-like 
fashion (Pl. XX. fig. 8). They form a gradational series on each side of the mesial line, 
the latter drawing representing the external appearance; then they become closer and 
closer, till the whole membrane assumes a streaked, granular aspect, and, finally, in the 
centre, a granular only. Anteriorly there are some longer tufts on each side, as seen 
in PL XX. fig. 9. The horny external portion is dotted by minufer specks. At the 
anterior margin the cells become larger and have distinct nuclei; and as the deep brown 
tinge of the harder texture اد‎ into the faint yellowish tint of the softer membrane in 
VOL. XXIV. ` 
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