VII. ON THE ORIGIN AND HISTORY OF THE URINOGENITAL 

 ORGANS OF VERTEBRATES 1 . 



RECENT discoveries 2 as to the mode of development and 

 anatomy of the urinogenital system of Selachians, Amphibians, 

 and Cyclostome fishes, have greatly increased our knowledge 

 of this system of organs, and have rendered more possible a 

 comparison of the types on which it is formed in the various 

 orders of vertebrates. 



1 From the Journal of Anatomy and Physiology, Vol. X. 1875. 



a The more important of these are : 



Semper Ueber die Stammverwandtschaft der Wirbelthiere u. Anneliden. 6V//- 

 tralblatt f. Med. Wiss. 1874, No. 35. 



Semper Segmentalorgane bei ausgewachsenen Haien. Centralblatt f. Med. 

 IViss. 1874, No. 52. 



Semper Das Urogenitalsystem der hoheren Wirbelthiere. Cenlralblatt f. Med. 

 Wiss. 1874, No. 59. 



Semper Stammesverwandschaft d. Wirbelthiere u. Wirbellosen. Arbeiten aits 

 Zool. Zootom. Inst, Wurzburg. II Band. 



Semper Bildung u. Wachstum der Keimdriisen bei den Plagiostomen. Central- 

 blatt f. Med. Wiss. 1875, No. 12. 



Semper Entw. d. Wolf. u. Mull. Gang. Centralblatt f. Med. Wiss. 1875, 

 No. 29. 



Alex. Schultz Phylogenie d. Wirbelthiere. Centralblatt f. Med. Wiss. 1874, 

 No. 51. 



Spengel Wimpertrichtern i. d. Amphibienniere. Centralblatt f. Med. Wiss. 

 1875, No. 23. 



Meyer Anat. des Urogenitalsystems der Selachier u. Amphibien. Sitzb. Natur- 

 for. Gesellschaft. Leipzig, 30 April, 1875. 



F. M. Balfour Preliminary Account of development of Elasmobranch fishes. 

 Quart. Journ. of Micro. Science, Oct. 1874. (This edition, Paper V. p. 60 et seq.} 



W. Muller Persistenz der Urniere bei Myxine glutinosa. Jenaische Zeitschrijt, 



1873- 



W. Muller Urogenilalsystem d. Amphioxus u. d. Cyclostomen. Jenaische Zeit- 



schrift, 1875. 



Alex. Gott-e Entwickelungsgeschichte der Unke {Bombinator ignciis]. 



