WILLIAMS: HABITS OF SCUTIGERELLA. 
475 
in any particular somite originate on the under side of the dorsal plates 
and are inserted on the inner surface of the coxa to move it in the 
different directions. In some cases fibers originate on the lower sur¬ 
face of the third scute in front of or behind the scute most nearly over 
the leg. These may unite with fibers whose origin is on scutes nearer 
the leg. 
Ecdysis. 
(Methods of ecdysis as derived from a study of the cast skins of 
adults.) 
Since Grassi (’ 86 , p. 597) stated that he had never found specimens 
of Scutigerella immaculata in ecdysis a number of the ecdyses of adults- 
cast in the laboratory were studied to determine the general method 
of shedding. 
No. 1. Torn laterally on the left side along and just above the coxae 
of the posterior legs. 
No. 2. Torn vent rally between posterior legs. 
No. 3. Opened at dorsal suture of next to last somite. Not torn, 
cerci flexed downward. 
No. 4. Slit lengthwise on ventral side for last 7 somites. 
No. 5. Head broken off, ventral wall partly torn. 
No. 6. Top of head gone, ventral wall torn, and the posterior seg¬ 
ments turned downward. 
No. 7. Torn on the ventral side between the legs of the last five 
somites. The anterior end all crowded. 
No. 8. Torn on the ventral side between the legs of the last six 
somites. The anterior end all crowded. 
No. 9. Torn from the fourth to the ninth segment on the ventral 
side. Segments 10 and 11 open on the dorsal side. Possibly the top 
of the head gone. 
No. 10. Torn all along one side above the coxae of the legs. Legs 
fastened firmly to the soil. 
No. 11. Cast broken in half at the 8th somite. Not torn. 
No. 12. Torn on the right side just below the coxae of the legs. 
Head much earth-stained and somewhat concentrated. Posterior 
end perfect. 
From these examples it is plain that the animal may escape from its 
cast skin either by tearing between the legs or just above the attach¬ 
ment of the legs on either side or by tearing the dorsal covering longi- 
