400 



ZOOLOGY 



eyes, and a circum-oesopliageal collar, whicli 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 



—10 



Fio. 228. — Transverse section through the body of Euscorpius italims in the 

 region of the endosternite. After Lankester. 



1. Alimentary canal. 



2. Caeca of gastric gland (liver). 



3. Anterior aorta. 



4. Endosternite. 



5. Supraneural plate of endosternite. 



The dotted areas represent sections of various nrascles, 



6. Right ventral nerve cord. 



7. Supraneural blood-vessel. 



8. Chitinous tergum. 



9. , , sternum. 

 10. Eight coxal gland. 



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 ; 



