SntucTUKF. OF THE Vextr.vl Sac is MASTWOt'FiyUS. 



Fiff. fi. ■Proin dishil tbini on left edfie of s:ic. 



Fig. 7. Fr..m proximal tlrrd. sliowin- plat.-s in normal position. , 



Fi.' 8 Fn.m proximal tlurcl. showing plates d ^u.rbod .xnd esposim; artun l.u tac ts^ 



All Kguro. ll.k.n tVon. :.704S. B-M^nnd enlarged 1>1. d.an.. Ihe .mall nu.nU.s 

 refer to iho ridges, as nunilx-red in the ie\t, p. l'.'^. -f.u-ti.rp 



The ;T/;/ar!//.r represent 8 the arli.s.'s lir.M and erroneous impression of 'ho >t nu ti.re. 



