Tho Marjjjinc'd Tmllc oci nrs Irtim WCsttMii New York to Iowa and 

 perhaps soutliwaid to Louisiana. \\ . IF. Smith says, (han in Oliio 

 this sptM'i«'s is abundant. It is ccitain Dial in the <'asl«'rn part of 

 IV'nnsvlvania the I'aintcd Turtle is found while in liic wcsit in jiait 

 the Mar^iinod Tuith' much jtrcdominalcs. 



Uur colU'cUons in I'cnnsvlvania have been from Kiie county, by 

 I'l'of. E. M. Mixer. Waterford. and Tio^a county, Mr. I). ('. Manicy, 

 Stokesdale. 



IJay says of the Margined Turtle, "II is at once our most beautiful 

 and most common tortoise (Indiana). Is strictly aquatic and exces- 

 sively timid. It prefers pond.'?, i)ools, ami (he sluggish parts of our 

 streams. May be often seen lying on some fallen tree trunk or on 

 some projecting stone basking in the sun. The sense of sight and 

 hearing app<'ar to be acute, for it easily takes alarm and tumbles 

 into the wa(er and disappears. It is then often to be found buried 

 in the mud, close to where it entered llie water. Is entirely harm- 

 less, and can hardly be provoked to bite." 



A comparison of the two species reveals some points of interest. 

 Among these are such as follows: 



C. prcta is regarded as a species in the process of formation from 

 C. marginata. It seems to have "freed itself" pretty well, as Hay 

 says, yet not completely. Intergarding forms are rather common. 

 In other words, the imitation jwriod has not come to a close. It is 

 impossible to distinguish with any degree of certainty the young of 

 the two species. Agassiz's figures of their shells and plates do not 

 show the true condition of affairs, although applicable to the ma- 

 jority of cases after they have made some growth. 



A series of specimens has been arranged, and photographed, and 

 is here published as our Plate \'III, showing gradations from the 

 marginata type to the picta type. These, from their geographical 

 range, and from their adult contemiioraries in the same pond in 

 certain cases, are undoubtably C. picta. Tiie youngest one shown 

 in this series is certainly like marginata in every respect. 



In general, the two species may l>e distinguisht^l when adnli by the 

 following characters: 



1. Geographical range. This is not infallible, as both sjx'cics may 

 occur in Western Pennsylvania and in Ohio, although the Allegheny 

 Mountains must be regarded as dividing their general respective 

 regions. 



2. Arrangement of plates on carapac*-. In wargi7iafii the side 

 (costal) and middle (vertebral) plates ai<' arranged alternately as is 

 common in turtles: in picta these are arranged opjvosite each other 

 BO that (hey form transverse rows across the back. 



