448 
LIVDE. 
EXPLANATION OF PLATES I-III. 
Fic. 1. This figure represents a ventral view of the principal part of the nervous 
system of Limulus, ensheathed by arteries, and enlarged X 2 from the specimen. 
Anterior oesophageal ganglion or brain. 
Oesophageal collar. 
Post-oesophageal ganglion. 
Abdominal ganglionic cord. 
Ganglia of the cord. 
Anterior ganglionic nerves. 
Posterior ganglionic nerves. 
Cut edge of the gill-plates. 
Cut edge of the operculum. 
Integumentary nerves. 
Nerves to the thoracic appendages. 
Nerves to the pencils. 
Nerves to the operculum. 
Nerves to the chilicerae. 
Nerves to the median eye. 
Nerves to the sub-frontal sclerite (olfactory organ). 
Nerves to the lateral eye. 
Nerves to the frontal integument. 
FIG. 2. This figure is a ventral view of a Limulus, of which the right half of 
the brain was extirpated, and that had forced movements to the left side. The 
appendages of the left side are bent on themselves, making the angle between the 
third and fourth segment smaller than the corresponding angle of the appendages 
of the right side. 
SfaiGe 
ch. 
ant. vent. 
app. 
ceph. car. 
pen. 
0. 
Cox. 
I-5. 
ab. car. 
p. a. C. 
J. 
Sub-frontal sclerite (olfactory organ). 
Chilicerae. 
Anterior ventral margin. 
Thoracic appendages. 
Cephalo-thoracic carapace. 
Pencils. 
Operculum. 
Coxae. 
Gill-plates. 
Abdominal carapace. 
Posterior abdominal corners. 
Spine. 
Fic. 3. This figure is a ventral review of the gill-plates in cramp position. 
0. 
I-5. 
Operculum. 
The gill-plates. 
Fic. 4. This figure represents the dorsal view of a gill-plate — natural size. 
& 
S. 
Gill-books. 
Parabranchial stigmata. 
