1856.] 



107 



lines above or beneath the eyes ; pupil black ; iris golden ; sternum black, seve- 

 ral of the plates tipped with yellowish ; marginal scutes narrow, except the t( ur 

 posterior, which are broad (Adult.) In younger specimens the yellow lines 

 above and below the eyes are manifest; shell ash, spotted with black ; sternum 

 yellow, mingled v^ith black, sometimas without spots; very young specimens 

 with radiating lines of black upon ttie carapax ; length of shell 3 inches 10 lines. 



Var. a. Carapax olive, with numerous black spots ; posterior terminal mar- 

 ginal plates larger than the others ; an orange-colored line above and one below 

 the eyes ; iris golden ; sternum yellow and black mingled ; soft parts ash colored, 

 with a tinge of red and yellow; younger specimens presenting the same general 

 appearance; shell inclining to brown above; sternum yellow. (K. guttatum, 

 LeConte.) 



Length of shell 3 inches 7 lines. 



Var. /?. Shell dark Spanish brown above, with numerous dark colored spots; 

 sternum black, mingled with yellow ; soft parts greyish. 



Length of shell 4 inches 4 lines. 



The Kinosternum guttatum of Major LeConte appears to be a variety of 

 Staurotypus odoratus, var. a. Dr. Holbrook's plate represents a young ash- 

 colored female. Schoepf's figure is also that of a female more advanced but not 

 fully grown. (Tab. 24, ,g.) Hist. Testudinum. Erlangae, 1752.* 



We believe Dumeril and Bibron to be right in putting the animal above de- 

 scribed in the genus Staurotypus. 



Cinosternon penusylvanicum differs from Staurotypus odoratus in the much 

 greater mobility of the posterior portion of the sternum, the animal being able 

 to close itself up, almost like a box tortoise, in the greater extent therefore to 

 which the sternum covers the ventral surface, in the marked differences in the 

 shape of the sternal scutes, which, with the exception of the abdominal, are more 

 or less triangular in penusylvanicum, in the larger size of the inguinal plates, 

 in the shape and coloration of the head, in the form and arrangement of the 

 posterior marginal plates, and in the configuration of the carapax. 



Staurotypus-j- belongs to the family of Elodites of Dum. and Bib., orPaludine 

 Turtles, which are placed immediately after the Chersites or Land Tortoises. 

 These are subdivided into two subfamilies the Cryptoderes and Pleuroderes 

 the first having the power of withdrawing the neck under the middle of the cara- 

 pax. It comprises seven genera, viz.: Cistuda, Emys, Tetronyx, Platysternon, 

 Emysaurus, Staurotypus and Cinosternon. 



The second sub-family, or that of the Pleuroderes, which have the power of 

 withdrawing the neck to one of the sides of the anterior opening of the carapax, 

 and never completely between the arms and under the middle of the carapax, as 

 in the Cryptoderes. comprises a'so seven genera, viz., Peltocephalus, Poducne- 

 mis, Pentonyx, S/ernotheerus, Platemys, Chelodina, Chelys. It will be observed, 

 therefore, that Staurotypus and Sternothjierus belong to different subfamilies, for 

 which reason we prefer to designate this animal as Dumeril and Bibron have done 

 by W agler's name of Staurotypus, the latter being a Cryptodere ; besides, Sterno- 

 th^erus has no nuchal plate, and is destitute of axillary and inguinal plates. 

 The marginal scutes are 24 in number. The sternum is not cruciform, as in 

 Staurotypus, the anterior valve (the only one) and the abdominal plates en- 

 closing the animal leaving the posterior parts more or less exposed, the poste- 

 rior part of the sternum being immoveable, or nearly so, as in Staurotypus. 

 Dumeril and Bibron also point out an anatomical difference of importance be- 

 tween the Cryptoderes and Pleuroderes, viz., that in the latter the pelvis is solidly 

 fixed to both the sternum and carapax ; whereas, in the former, it is " articulated 

 to the internal face of the carapax by a cartilaginous symphisis, corresponding to 

 the sacral bf^ne, being entirely free towards the sternum, permitting several of 



* Mr. Gray, Major LeConte and the Prince de Canino, place it in Cinosternon ; 

 Prof Holbrook and Mr. Bell, in Sternothaerus. 



f 2Tay/)oc, cross, and tutto;, type sternum cruciform. 



