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THE AMERICAN NATURALIST [Vol. XL, 



(4) Anotlier slender i 

 (ventral to) the correspor 



[vliere the dors 

 ;oinewhat ani 

 )dontophoral 



1 each side passes hack beneath 

 ramus and is inserted at the end 

 of the ramus on the convex ven- 

 tral surface — convex root (Figs. 

 11, 14, con.). 



Thus the larger part of the 

 rdractor is inserted into the wall 

 of the proboscis, while the smaller 

 portion finds insertion on the car- 

 tilage frame. 



As stated. tlu>sc tour roots unite 

 iiiit(M-ii)rlv to IdiMii what maybe 

 called the (/real retractor of the 



ventral and two lateral tendons 

 into theradular sac (Fig. 14, ten.). 

 I liese tendons and their muscular 

 -iiiitinuatioiis I'uii m the doublv 

 ^T(M)\cd i-(.ad\vav formed by the 

 _ioox,d dot.d >uit utsof the two 

 <'artilao;e rami, these being close 

 together anteriorly, held so by 

 cross hbers that pass between 

 them. 



One set of these cross fibers 

 forms what may be called the 

 ventral sheet of cross fibers, passing 

 from the convex ventral surface 

 of one ramus to that of the other 

 (Figs. 10, 11, vscf.). This sheet 

 extends from the beginning of the 



:her) ends; the ventral sheet ends 

 lorsal sheet. In describing the 



