400 ZOOLOGY 
eyes, and a circum-oesophageal collar, which gives off the 
ventral nerve cord (Fig. 227). The nerves to the first six pairs 
of appendages, as well as to the genital plate, the pectines, 
and the two following segments, arise from the collar or the 
sub-oesophageal ganglion. The ventral cord for some distance 
bears no ganglion, the first being situated in the eleventh seg- 
ment and supplying the third pair of lung-books. Behind 
this there are six pairs of ganglia, one in each segment, the 
Fic. 228.—Transverse section through the body of Huscorpius italicus in the 
region of the endosternite. After Lankester. 
1. Alimentary canal. 6. Right ventral nerve cord. 
2. Caeca of gastric gland (liver). 7. Supraneural blood-vessel. 
3. Anterior aorta. 8. Chitinous tergum. 
4. Endosternite. a: 46 sternum. 
5. Supraneural plate of endosternite. 10. Right coxal gland. 
The dotted areas represent sections of various muscles. 
last being in the fourth metasomatic segment. The sense 
organs are the simple eyes ‘borne on the carapace, one pair 
near the middle line, and a small group on each side near the 
edge, and the pectines, which may be tactile in function. 
The poison glands are two in number, both situated in 
the postanal spine. They are provided with a muscular tunic, 
the contractions of which serve to express the poisonous 
secretion. Each gland has a duct, and the ducts open by 
separate orifices close to the apex of the spine. The poison 
is fatal to most small animals, such as spiders and insects ; 
