54 Journal of the Mitchell Society [September 



should tho line be drawn to separate these forms into two species? 

 Fiirtlierniore. females havinfr one type of plastron may produce 

 olTspring of entirely different markings. T"'^nf()rtiinately, the plastron 

 markings of turtle No. 2o, from which embryos No. 115 and No. 116 

 were secured, is not known ; however, these embryos, the plastrons of 

 which, drawn to scale, are shown in figures 2o and 26, were taken 

 from the same clutch. The former shows a typical C. hellii plastron 

 while the latter shows the plastron typical of C. cinerea. There were 

 two other embryos in this clutch which are not figured; one has a 

 plastron marking smaller than that shown in figure 22, while the 

 other is intermediate between figures 21 and 22. There is, evidently, 

 only one species occurring near Madison, or else there is a hopeless 

 hybridization. If the latter be true, it is unaccompanied by any 

 partial sterility such as is usually the case. The relation of these 

 color patterns to geographical distribution in Wisconsin has not been 

 worked out. In Michigan (Ruthven) C. hellii occurs in the upper 

 peninsula while C. cinerea occurs in the other parts of the state. It 

 would be interesting to find the results in other regions where both 

 forms occur. It seems probable that in regard to these animals the 

 case is similar to that of the song sparrow. In the central region 

 of the distribution we have a mixture of all forms which, west of 

 the I\lississippi River, grades through hellii into oregoniensis, and 

 eastward, into cinerea and possibly into picta. On this basis the 

 classification would be Chryse)niis cinerea and Chrysemys cinerea 

 var. helli. If this classification is adopted or even the rule of priority 

 is applied, then the work of Allen (1904-1906) and that of Van 

 Alten (1914-16) should be designated as being upon Chrj/sonys 

 cinerea rather than Chrysemys marginaia. In this paper the forms 

 are designated as Chrysemys cinerea and no effort is made to dif- 

 ferentiate the varieties. 



During the collection of the material opportunities were afforded 

 to observe the egg-laying habits of this turtle. In 1919 this species 

 was found to be laying betAveen June 8 and June 26. One female 

 was taken upon high ground June 28, but no nest was found to 

 prove that she had just laid. Dissection showed no eggs in the ovi- 

 duct. 



Collections during the summer of 1920 gave slightly different re- 

 sults. The first turtle taken in oviposition was collected June 8. 

 However, the laying lime was considerably extended. No turtles 



