33S 



PROCEEDINGS OF THE ACADEMY OF 



[July, 



and velar row (v), while the buccal ganglia (be) lie at the right and 

 left_margins of the blastoderm. Posterior to the animal [pole is 



Diagram illustrating the more important phases in the overgrowth of the yolk 

 by the blastoderm in Fulgur carica. The outer circle represents the out- 

 line of the entire egg, and the smaller circles, numbered 1 to S, represent 

 the margins of the blastoderm in successive stages of the overgrowth. The 

 egg is represented as seen from the posterior pole, and in order to bring all 

 stages into one figure the arc through which tiie posterior margin of the 

 Ijlastoderm moves is represented as less than is actually the case. The out- 

 line of the blastoderm and the positions of the organ primordia in stage 1 

 correspond to figs. 25 and 26, plate XXATI ; stages 2 and 3 correspond to 

 fig. 27; stage -4 to fig. 28; stage 5 to fig. 29; stages 6 and 7 to fig. 30; stage 8 

 to fig. 31. In stage 1 the velar cells are represented as a double line of 

 stipples anterior and lateral to the cerel^ral ganglia (cb) ; the buccal ganglia 

 (be) lie at the lateral margins of the blastoderm ; immediately posterior to 

 the shell gland (.s) is the primordium of the intestine; on the left of this is 

 the alidominal ganglion, and on each side of tlie latter are the parietal ganglia, 

 the pleural ganglia, the otocysts and the pedal gangHa. In stages 2-7 the 

 cerebral ancl buccal ganglia are represented in dotted outlines ; in stages 1 

 and 8 they are stippled, as are the other primordia. 



found an organ complex which includes the shell gland, intestine, 

 abdominal, parietal, pleural and pedal ganglia, and the otocysts. 



By the growth of the median anterior portion of the blastoderm, the 

 cerebral ganglia and velar cells and the buccal ganglia are carried 

 around to the successive positions indicated in the diagram, while the 

 organ complex described above undergoes little movement. The dia- 

 gram is faulty in that it shows too little movement of the organ com- 



