310 
BULLETIN OF THE BUREAU OF FISHERIES. 
eggs are attached exclusively to the long silken tufted hairs of the inner branches of 
the second, third, fourth, and fifth pleopods. They are distributed, therefore, in 8 
bunches, with over half a million eggs to a bunch. The appendages are flattened, and 
excepting the anterior face near the tip and a portion of the posterior face near its base, 
the endopodite is studded with remarkably long silken setae. Bach hair carries from 
1 50 to 200 eggs, and each egg is glued by an independent stalk to the hair. Each egg 
is, moreover, extremely minute, measuring about of an inch mm.) in diam- 
eter, or smaller than the dot of the letter i of this type. The hairs are extremely 
slender, varying in diameter from of an inch at base to yyy of an inch at middle, 
beside which a human hair is very coarse and a silken thread a veritable cable. These 
attenuated hairs taper gradually to a sharp point. 
The exopodite of the swimmeret is fringed with a dense row of plumose setae, which 
are not more than one-fifth as long as the egg-bearing hairs of the inner branch and 
which, according to Williamson, serve in Cancer as a barrier to prevent the escape of 
the ova from the brood-chamber before they become attached. Strange to say, they 
do not catch a single egg. 
Upon the theory of Williamson, and the assumption of an average cargo of 
4,500,000 eggs, we can appreciate the nice work in fencing which would have to be per- 
formed by the silken hairs of Callinectes and indirectly by the appendages of the crab. 
Some 22,496 hairs would be required to spear and string 200 eggs each, and the feat 
would have to be done in the dark, as it were, and upon an egg so small as to be hardly 
visible upon the point of a fine cambric needle. But this is not all; the thrusts of the 
hairs must pierce a perivitelline space, that is, penetrate a tough chitinous membrane 
and be deflected from a semiliquid envelope. If this really happens, it is certainly a 
most wonderful performance. 
Our objection to such a theory of attachment is based upon general principles, 
and before accepting it we should wish to have answers to the following questions. 
How is it possible for these delicate hairs to spear anything, and least of all solid spheres 
like an egg, suspended in water, and therefore in unstable equilibrium ? The hairs 
have no more rigidity than a silken thread; they can hardly stand alone; and when 
loaded with eggs at their tips the spearing of additional eggs would seem to be impos- 
sible. (2) How is it possible for a spear or needle to penetrate the tough outer coat and 
avoid piercing the egg, for the suppositional inner membrane really does not exist at 
the time the egg is laid ? (3) Are the almost microscopic eggs pushed along like beads 
on a string or birds on a spit, 200 or more crowded in line, and each leaving a viscous 
trail, without clogging the line, sticking together, or crowding one another off ? (4) How 
is it possible for drops of an albuminous liquid to ooze from a hole in an egg without 
spreading over that egg, for a hair in contact with the egg would certainly not conduct 
this liquid against the force of gravity, and myriads of eggs must occupy every position 
with respect to the hair? Perhaps we can get a better idea of the physical difficulties 
involved by imagining a fly-fishing rod reduced to great tenuity and used as a spear 
for apples. How many apples of whatever size could its tip hold? 
