OF THE AMERICAN KING-CRAB. 475 
. Premaxillary Nerve.—This, with a more posterior origin than the mandibular nerve, 
repeats the characters of that nerve, in relation to the fourth limb, or homologue of the 
* preemaxilla,' or first or anterior maxilla, in higher Crustaceans. The nerve (» v) is 
shown in Plates XXXVII. & XXXVIII., entering and traversing the * coxa’ and ‘basis’ 
of the limb marked V. This limb is sexually modified in the male of Limulus mo- 
luccanus, but not in the species here dissected. 
Fifth Epimeral Nerve (n 9, Pl. XXXIX .).—This repeats the relative position of origin 
to the premaxillary nerve which the antecedent one (n 8) bears to the mandibular nerve, 
and holds the same relation in its course to the apodemes rv & v. It forms the plexus 
beneath that of the optic nerve, beyond which the filaments are lost in the tissues there. 
The optie nerve crosses dorsad of the first four epimeral nerves in its course to the 
compound eye. 
Postmaxillary Nerve.—The fifth limb-nerve (n vr, Pls. XXXVII. & XXXVIIL.), 
with a more posterior origin and a course more obliquely backward, repeats in limb vt. 
—the homologue of the postmaxilla, or second maxilla, in higher Crustaceans—the 
characters of the * premaxillary nerve' in relation to limb v. 
Sixth Epimeral Nerve (n 10, Pl. XXXIX.).—This repeats the same relative position 
of origin to its answering limb-nerve as does # 9; it is continued further obliquely back- 
ward before bending outward to its interapodemal space, and bifureates before entering 
there, the hinder division descending to supply the strong adductor muscle of the sixth 
limb (vir in Pls. XXXVII. & XXXVIIL.). 
Masxillipedal Nerve (n vii. Pls. XXXVII. € XXXVIII.).—The nerve supplying 
that limb has its origin between the postmaxillary nerve and the beginning of the abdo- 
minal ganglionic chord y. It repeats the character of the antecedent limb-nerves in 
relation to its own articulated appendage, which is the homologue of the * maxilliped’ in 
higher Crustaceans. 
Palpal Nerves.—At the interspace between the origins of the postmaxillary and maxil- 
lipedal nerves, as in that between the latter and the ganglionic continuation of the neural 
centre, arise filaments which supply the spinigerous process or ‘palp ' of the compressed 
denticulate haunch-joint (Pl. XX XVII. figs. 2 & 5, p). 
Chilarian Nerve (Pls. XXXVII. nx, & XXXVIII. n *). This rises between the 
origins of n vit & n VIII; it is appropriated to and richly ramified in the leaf-like 
spinigerous appendage, articulated behind the base of the maxilliped, and closing pos- 
teriorly the circumoral armature. The serial homology of the chilarian with the palpal 
nervules lends some countenance to that of the appendage, so supplied, being a detached 
spinigerous process or * palpus ' of vit. 
Seventh Epimeral Nerve (n 11, Pl. XXXIX.).—This arises dorsad of the origin of the 
maxillepedal nerve, passes backward and outward to its proper apodeme (v1), where it 
divides, and, running onward, ramifies to supply the tissues in the hinder produced angles 
of the cephaletron. 
Eighth Epimeral Nerve (n, 12, Pl. XXXIX.).—This is one of the same system of dorsal 
nerves, succeeding the seventh; it passes backward and slightly outward along the dorsal 
3 S 2 
