BOTRYLLUS I'O LYO YC L I S . 



73 



a 



mJi^ : W 



FIG. 127. - Systems of individuals of Botryllus polycyclus. Much 

 enlarged. (Savigny, pi. xxi, ff. I 1 and I 2 .) a. A. system in a state 

 of contraction, seen from above. 6. A system in a state of dilata- 

 tion, seen from the side. B, branchial aperture ; C, atrial aperture ; 

 N, common excretory cavity ; k, tentacular filaments ; (3, y, c, 8, 

 sj'stems commencing to develope. 



FIG. 128. Individual of Botryllus polycyclus. Much enlarged. 

 (Savigny, pi. xxi, ff. l :t and I 4 .) . Eight side. b. Left side. B, 

 branchial aperture ; C, atrial aperture ; c, stomach ; c, CEeciim of 

 the stomach ; D, nerve-ganglion ; d, intestine ; F, branchial sac ; 

 g, intestinal loop; H, anal aperture; h, anterior (branchial) 

 tubercle ; K, ovary ; k, posterior tubercle ; 1, dorsal lamina ; t, " egg 

 or germ" out of the ovary and approaching maturity; Y, ceso- 

 phagus. 



