34 
STIQMATIC OPERCULA IN THE SCORPION. 
tLat liiglily irritating and corrosive siilDstances, sucli as the 
fumes o£ nitric acid, will make the animal shut the stigmata. 
Chloroform seems to produce some efiect. But all the 
stigmata are not completely closed dui'ing the whole time 
that the animal is in it, a state of things which can be 
observed vvhen the scorpion is put under water. In one 
instance, I observed in a scorpion which was placed in 
chloroform vapour, the stigmata which were previously 
shut, open after a time and remain in that condition, to 
jar, the pectines may be seen to move about and used like 
feelers. They possess a great range of movement. When 
the animal is uncomfortable, as when placed in chlorotorm 
vapour or gradually heated, the pectines may bo seen 
moving after the rest of the body is still. 
In Thelyphouus, the openings of the two pairs of lung- 
books are hidden by prolongations of the sterna. Proba- 
bly, an arrangement exactly similar to that connected with 
the stigmata of the scorpion, does not obtain. These and 
other points in the anatomy of that interesting and little- 
known Arachnid, I hope to be able to determine on a future 
occasion. 
