Zoologischer Anzeiger 



herausgegeben 



von Prof. J. Yictor CarUS in Leipzig. 



Zugleich 



Organ der Deutschen Zoologischen Gesellschaft. 



Verlag von Wilhelm Engelmann in Leipzig, 



XY. Jahrg. i8.Juiii892. No. 396. 



Inhalt: I. Wissenschaftl. Mittheiluugeu. 1. Davenport, The (Jerm-layers in Bryozoan buds. 

 2. Koenike, Anmerkungen zu Piersig's Beitrag zur Hydrachnidenknnde. 3. Bergli, Die Drehung des 

 Keimstreifens und die Anlage des Dorsalorgans hei ffam»»a»-?(s pulex. 4. McMarrieli, The formation 

 of the Germ-layers in the Isopod Crustacea. II. Mittheil, ans BInseen , Instituten etc. Linnean 

 Society of New Soutli Wales. III. Personal-Notizen. Litteratnr. p. 165—172. 



I. Wissenschaftliche Mittheilungen. 



1. The Germ-layers in Bryozoan buds. 



By C. B. Davenport , 

 Zoological Laboratory, Harvard Coll., Cambridge, Mass., U. S. A. 



eingeg. 14. Mai 1892. 



In the Zoologischer Anzeiger, No. 387, Dr. Braem makes three 

 points against me: I) That in my recent paper (1891) I have assigned 

 to him a view (the entodermal nature of the inner layer of the Bryo- 

 zoan polypide bud, and its origin by gastrulation) which he has never 

 held and never uttered; 2) that, on the contrary, the idea supported 

 by me (p. 88) that the inner layer of the polypide bud is »neither ecto- 

 derm nor entoderm but indiiferent« only later becoming differentiated 

 into ectoderm and entoderm agrees with that previously defended by 

 him (Braem, 1890) ; and 3) that in my conclusion concerning the part 

 played by embryonic tissue in budding I have overlooked his previ- 

 ously published conclusion which completely included mine. 



In justice to Dr. Braem and myself I desire to make the follow- 

 ing explanation. 



1. Upon re-examining the passages referred to by Braem I am 

 convinced that I was in error in interpreting him as I did. This error 

 I regret. 



2. I should never have suspected from reading Brae m 's paper 

 (1890) that he held the same view as I expressed. For he repeatedly 

 referred to the inner layer as being derived from the ectoderm of the 

 larva (Braem, 1890 p. 116, 121; 1892 p. 114). To be sure, he agreed 



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