808 DR. HANS GADOW ON OVARIES 



PAPERS. 



48. The One-side J Kediiction of the Ovaries and Ovid acts in 

 the Amniota, with Remarks on Mammalian Evolution. 

 By Hans Gadow, M.A., Ph.D., F.R.S., F.Z.S. 



[Received May 31, 1912: Read June 4, 1912.] 



Index. „ 



Page 



Anatomical Structure and Development 803 



Sanguine morphologists reckon that it takes about ten years 

 for their discoveries to find their way into a text-book. It 

 takes a generation to eradicate erroneous statements, especially 

 generalisations, out of such books, since most of them are 

 repeated from others without consultation of the immense host 

 of orio-inal papers. And it is apparently hopeless to expect the 

 enthusiast or amateur to appreciate the difference between a 

 generalising text-book of comparative anatomy and a zootomical 

 account. It means progress for a branch of science if we can 

 inscribe upon its statute-book a few lines of true generalisation, 

 which, if there be no hedging, require no longer any concrete 

 examples to be mentioned. If only partial generalisations are 

 possible, of course the exceptions are to be recorded and every 

 new case is welcome, until their accumulation in turn permits of 

 being summarised. Then let there be drawn a line, and let the 

 discoverer of further cases keep his peace unless he has something- 

 new to say. 



The condition of the bird's ovaries and oviducts is a case in 

 point. The main facts have by now become ancient history and 

 general knowledge to the zoologist, so ancient that the original 

 workers have been forgotten, as much as the name of the 

 originator of the term morphology. 



That the ovaries and ducts of birds are one-sided v/as probably 

 known since time immemorial. Perrault * described and figur-ed 

 them in the Ostrich without further comment. In the year 1810 

 Wolf mentioned that he had usually found two ovaries in the 

 Sparrow-hawk, a fact duly incorporated by Tiedemann f in his 

 excellent work, which reveals him as a zoologist far ahead of his 

 time. Next, Spangenberg J figured the right ovary in a Duck. 

 Barkow § described the occurrence of right-sided rudiments of 

 the female generative apparatus in various other birds. Emmert || 

 observed equally large right and left ovaries in the Sparrow- 



* Peeeault : M^moires pour servir a riiistoire naturelle. Amsterdam, 1736. 



t Tiedemann: Anatomie und Naturgescliiclite der Vogel. 1810. 



j Spangenbeeg : Disquisitiones circa partes genitales fcemineas Avium. Got- 

 tingEe, 1813, 4to. 



§ Baekow : Von der Kloake verscliiedener Vogel. Meckel's Archiv f. Anat. u. 

 Phys., 1829. 



II Emmeet: Reil u. Authonrict's Archiv. 



