122 ILLINOIS STATE ACADEMY OF SCIENCE 



THE NASAL CAPSULE IN NATRIX CYCLOPION 



Nina Wicks, Knox College. 



introduction 



Thus far little work has been done on the chondro- 

 crania of reptilia. More investigations have been made 

 upon fishes and amphibia than on the reptiles, birds and 

 mammals. 



Kunkel (1912) on "The Development of the Skull of 

 Emys lutaria" gives a good description of the chondro- 

 cranium of this reptile, and includes several plates. Par- 

 ker (1878) describes the structure and development of 

 the common snake, Tropedonotus Natrix; and again in 

 1879 discusses in considerable detail the skull of the 

 lizard. Parker gives more attention to the character of 

 the older stages and less to the actual developmental pro- 

 cess of the earlier larvae, thus making his contribution 

 of less value to this investigation since he has little con- 

 cern for the ethmoidal region. Gaupp (1900) describes 

 the chondrocranium of Lacerta agilis, one of the lizards, 

 showing a typical ethmoidal region which in some ways 

 is a repetition of the work of Born (1876) on the nasal 

 organ and the related structures of both the amphibia 

 and certain amniota. Seydel (189H) gave several new 

 facts concerning the nasal capsules. 



Higgins (1920) in his work on "The Nasal Organ in 

 Amphibia" figures a capsule of an older Amblystoma 

 which bears a striking resemblance to that of Natrix, 

 as will appear in the sequel. 



This paper was undertaken with the idea of ascertain- 

 ing the relation of the reptiles to the more specialized 

 amphibia as well as to the higher amniota. Natrix 

 cyclopion was selected as the reptilian type; although 

 perhaps not the most primitive, yet it possesses certain 

 characters that relate it to primitive conditions. 



The material which forms the basis of this study con- 

 sists of two embryos of different ages which were secured 

 through the kindness of Prof. L. A. Adams of the Uni- 

 versity of Illinois. The method of removing the embryos 

 from the females is most satisfactory, for it insures 

 complete identity of the species thus worked upon. The 



