(34) 

 0^^ the colly,'"-t nuik and ventral .ixea enterics. 



IL ia KiV opinion tiiat the cavity of the trunk id for'neo in 

 the followin*: inanner. As the tentacles i^row out and increase 

 in number, the posterior rej^oi. of the larva about ti^e rectum 

 increases greatly in length. lii aoing the latter, the luesoder- 

 mel linin;: of the collar is dravvn away from the somatic wall in 

 the region back of the tentacular banc, •■na a cavity in left con- 

 taining the rectum, part of tj:e stomach and ttie proximal part of 

 thie nephridial diverticula. At tne sane time this is takiii^, 

 place , certain cells, v/hich I believe have their origin from tiie 

 base of the nephridial diverticula, give rise to the lining of 

 th.e cavity o "^ t-^e truiik. As to the manner o ■•" origin of tiiese 

 cells I am still ixi aoubt. 1 have not been aole to fina tv.'O 

 coelomic sacs wj;ici. Hatschek (6) seeius to have fLj-iUrea (It is 

 possible that nis figure is meant to represent a sinj-;le sac cut 

 at two places) aiia I have nun tea for them in larvae vri.ero the 

 diverticula are Just beginnin.. to form ana also in larvae v:i tli 

 t'.TO , four and six tentacles. In one specimen -.vith tv.'o tentacles 

 hov/ever, ("F'ig.SO) I iiavc founa an arrangement of meaoaermal 

 cells on the dorsal side of the intestine whicn seems to be the 

 beginning of a sac; this, however, is net paired. V/hetiier this 



sac and its cavity give rise to tne lining and cavity of t.;e 



or not, 

 trunk 1 caiuiot sa:^ for 1 have founa but one specimen in v/nich 



