Plate XXVIII. 



Fig. 49. — Anterior portion of a median sagittal section of a larva of 14 



tentacles, x 2 F. 

 Figs. 50 (a-c). — Three transverse sections of a larva of 14 tentacles ; a 



through the stomach diverticulum (dii\), h obliquely thmugh the 



postoral septum {incs.), and c above the pouch pore, x "2 D. 

 Figs. .51 {a, h). — Longitudinal sections of the nei)hridiuni of a larva of 16 



tentacles, x 2 F. 

 Fig. 02. — Transverse section through the junction of the stomach and the 



te.so})hagus of a larva of IG tentacles^ showing the rudiment of tlie 



dorsal vessel {<l.v.) x 2 imm. ^Z,.. 

 Figs. 53. — Section of the above larva, through the cor[tuscular mass Avhich 



floats in the collar cavity. x 2 F. 

 Fig. .34.— Sagittal section through the right side of the iesu]ihagus of a larva 



of IG tentacles, x 2 F. 

 Figs. ,3.3 {ti and b). — Cross sections of a larva of 1 G tentacles. In the figure 



('. is re[)iesented the right halt' of tlii' section which ]i,isses tlirough 



the ston^ach (.sY>».) and the adult collar cavity (.s.r.r.) ; b througli the 



junction of the stomach and the intestine, whereto the contractile 



eœca (r.c.) are attached. x 2 F. 



(/'Vf/.s'. .36-.37 art drairn front hrrud' hi'loiKjliKj to f/jpc C) 



Figs. 5G {n-c). — -Cross sections of the \\<\A, where the multicellular gland is 

 represented in diiferent planes. x 2 1). I^etter // omitted. 



Figs. 57 («-e). — Cross sections through the trunk of a larva of 22 tentacles; 

 a under the magnification of 2 x 1) ; b a ])ortion of the trunk 

 walls containing the nephridial canal, magniiicd 2 x F with the 

 tube out ; c shows a portion of the v(3utral mesentery near the gut, 

 magnified 2 x F. 



