THE HORSE FOOT CRAB. 259 
off, and desert the imprisoned limb, and in due time would 
reproduce the lost member. 
The position of the mouth, and the masticating process 
are so peeuliar, that a description should not be omitted. 
The King Crab has six pairs of feet; although by some, 
those constituting the extreme anterior pair are called anten- 
ns, being greatly shorter than the others. The four pairs 
between this first pair, and the last pair, have a functional 
structure differing from the anterior and posterior pairs. Of 
these four pairs, the basal joint, or haunch, of each limb is 
flattened and smooth on each side, as though they were a 
series of plates intended to work upon each other, as the 
keys of an organ under the fingers of the musician. The 
external edge of each is rounded, and beveled like the edge 
of a carpenter’s chisel. Thus these flattened haunches lie 
against each other, their rounded edges directed backward 
at a considerable angle. The beveled edges (which are the 
exposed parts) of these projections are covered with very 
sharp incurved spines, overhanging and pointing into the 
oral aperture; for it is between these four pairs of spine- 
clad haunches that the creature’s mouth is situated. Each 
of these basal spines is articulated, and is set in the crater, 
or cup, of alittle teat-like prominence. These then, are the 
true jaws of the animal’s mouth; and as there are four pairs 
of these manducatory joints, the creature’s mouth is set in a 
line between eight jaws. These spiny teeth have, by their 
articulation, an amount of mobility in their little pits, which 
is eminently serviceable and preservative. Of these chew- 
ing teeth, though the number is variable, an individual can 
scarcely have less than one hundred and fifty. 
Wishing to see what their food might be, and how they eat 
it, I placed a specimen, hatched the preceding summer, in a 
small aquarium, and supplied it with plenty of fresh and 
tender sea lettuce (Ulva latissima). But this sea salad re- 
mained untouched, although the young Limulus had no other 
fare for three weeks. In fact, famishment had rendered it 
