OF THE AMERICAN KING-CRAB. 471 
Some small fasciculi, combining their insertions with the proper muscles of the 
branchipeds, have attachments to the thoracetral entapophyses, and seem to combine a 
levator action upon the branchipeds with that of the * depressores thoracetri.’ 
In the cephaletral limbs (rrr-vr, Pls. XXXVII. and XXXVIII.) the haunch-joint 
(coxa, 1) is of great transverse extent, and besides affording insertion to the apodemal 
muscles, which forcibly work the carding-plate, or * palpus’ (Pl. XXXVII. figs. 2-5, p), 
gives origin to muscles acting on the second joint or * basis’ (ib. ib. 2). 
Extensor basis pedis.—One of these, of small size, is an extensor of the * basis’ 
(Pl. XXXVII. fig. 5, a), but only in a slight degree. 
The * flexor basis’ (ib. b) is a larger, especially broader, muscle, and bends the * basis’ 
forcibly upon the * coxa’ or first joint. 
Flexor meri cnemiique.—The muscle (ib. d) arising from the ‘ basis’ (2) is supple- 
mented by other fibres from the * merion,' or third joint (3), proceeding penniform-wise to 
an entapophysis, c, attached to the base of the * enemion,' or fourth joint(4). The action 
of this series of fibres is to bend both merion and enemion. An ‘extensor of the cnemion ' 
is feebly developed. 
Flexor propedis.— The cavity of the cnemion is chiefly occupied by the penniform 
flexor, f, of the ‘propes’ (5), upon which it acts chiefly through the medium of the 
* apodeme;' e, attached to the base of that joint. 
Flexor dactyli-—1In like manner the penniform muscle, in the swollen basis of the 
propes, draws, through the medium of the entapophysis, y, the dactylus, s, powerfully, in 
contact with the claw-like process of the propes, 5 
In the propes, or fifth joint, of the maxilliped, fasciculi of the muscular fibres are 
grouped to be inserted into the short basal apophyses of the lamelliform appendages 
(Pl. XXXVII. fig. 4,6, £), which they tend to approximate, or to close upon or around 
the terminal chela (ib. 1). These plates, which radiate from the end of the * propes ” 
like the petals of a flower, are expanded by being pressed against the mud or sand, 
and seem to require muscles only for closing them, so as to facilitate the withdrawal 
of the limb. The application of the maxillipeds in locomotion was observed by W. A 
Lloyd, Esq., the constructor of the Aquarium at Hamburgh, of which he was for some 
years the conservator, and subsequently the constructor of that at the Crystal Palace, of 
which Aquarium he is now the manager. 
At Hamburgh, specimens of Limuli were kept alive from the year 1865 to 1870. From 
his observation of these Mr. Lloyd informs me, ** The ulterior pair of limbs" (maxillipeds, 
vir) “are not employed for walking, but exclusively for burrowing. These limbs are 
terminated by four long stiff lobes of an oval or leaf-shape, jointed at the base, on the leg, 
and capable of being opened and closed in a four-radiate manner. When it wishes to 
burrow, these two limbs are, sometimes alternately and sometimes simultaneously, thrust 
backwards below the carapace, quite beyond the hinder edge of the shell; and in the 
act of thrusting, the lobes or plates on each leg encounter the sand, the resistance or 
pressure of which eauses them to open and fill with the sand, a load of which at every 
thrusting operation is pushed away from under the crab, and deposited outside the 
carapace. The four plates then close, and are withdrawn closed, previously to being 
