DR. W. C. MSINTOSH ON THE HAIRS OF CARCINUS MJENAS. 97 
there is a collar of small curved teeth, continued along the shorter limb, chiefly 
at its inner margin (Pl. XX. fig. 21). The soft organ* (penis) which projects from the 
opening of the ejaculatory duct at the base of the last limb has numerous branched 
hairs over its surface and sides, chiefly at the base. 
Abdominal Hairs of the Femole.—The outer margin of the abdomen is fringed with 
most beautiful feathered hairs of considerable length, and possessing the double outline 
and semi-jointed condition so often noticed before. 
First pair of Abdominal Feet.—The internal limb is clothed for the most part with 
long, delieate, silky hairs, which are simple throughout, with the exception of some 
branched hairs at the base, best seen on the anterior surface of the foremost limb. The 
former are pale and translucent, and come off in distinct bundles all the way up from 
their commencement. The tufts above the middle joint arise from the upper part of 
each of the pseudo-joints that compose the flabellar extremity, being situated, likewise, 
only on the posterior surface and sides of the limb,—the anterior surface being free. 
The hairs themselves are very beautiful, presenting externally a brownish or yellow out- 
line, within this a pale streak, and then a more or less granular central portion. 
Attached to these hairs curious appendages are often found—long, trumpet-shaped, 
membranous bodies, which are yielding and soft, and somewhat fibrillated. The external 
limb is covered with branched hairs from base to apex along both outer and inner edges, 
the hairs on the outer row being rather longer than those on the inner. <A few short, 
smooth bristles are distributed over the general surface of the limb. Parasitic struc- 
tures often cover these hairs, tip, branch and limb; and occasionally they are bound 
together by the meshes of the byssus of a bearded Mussel. 
The same description applies essentially to the hairs of the other limbs, so that it will 
be unnecessary to repeat it. : 
The ova, when present, are attached solely to the inner limb of each abdominal 
appendage. It would seem strange, at first sight, that simple smooth hairs should be 
selected for the purpose of egg-carrying, while branched or brushed ones, which have 
more points of contact, are not employed. The examination of an egg-bearing female, 
however, dispels all doubts. It is found that these curious structures of fibrillated 
aspect, mentioned previously, which crowd the field of the microscope in many cases 
where the eggs have been ruptured and disappeared, are the pedicles or cords by which 
they were attached when present. A peculiar secretion seems to be developed, which 
coats each hair (often two together) with a tough investment, and bundles of whose fibres 
every now and then strike off to form the pedicles of ova, yet without diminishing the 
bulk of the coating on the hair beyond. These pedicles have a fibrillated aspect, and 
widen out as they touch the ovum; and the fibres, spreading for some little distance 
around, become lost on the capsule (Pl. XX. fig. 19). The attachment seems to be 
intimate and strong, since, after rupture of the ovum, this portion of the capsule clings 
firmly to the pedicle, as if it were a part of itself (Pl. XX. fig. 18) 22 
Development of Hairs.—In Carcinus menas in the act of exuviating, a membranous 
layer, apparently corresponding to the “ uncaleified corium " of Prof. Huxley, is found, 
* Fide Prof. Owen's Lectures on Comp. Anat., Invertebrata, p. 328. 
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