GEMMILL. TWIN GASTRULiE 

 AND BIPINNARI^ OF LUIDIA. 



PLATE I. 



Fig. 1. 



Fig. 2. 



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Fig. 4. 



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Fig, 6. 



Fig. 9. 



NEW SERIES. — VOL. X. NO. 4. MAY, 1915. 



2 p 



