284 AMERICAN TESTUDINATA. Part II. 



glotticlis, and also over the edges of the cornna hyoidea, there exist a great num- 

 ber of dehcate fringes, resembHng, especially on the hyoid arches, the fimbriated 

 gills of the Menobranchus or the intei'nal gills of a Tadpole."^ Before reading 

 this paper, we had noticed these organs; but, after seeing this Turtle remaining 

 under water for half an hour without showing the least sign of oppression, it 

 seems plausible to assume that these fringes may be similar to the internal gills 

 of Tadpoles, not only in their shape, but also in their fiu\ction. There exists, 

 moreover, an extensive network of l)eautiful vessels, spreading in elegant dendritic 

 ramifications upon the whole loAver surface of the Trionychida3, which can hardly 

 have another function than that of assisting in the process of breathing, as they 

 are too numerous and too large to be ccmsidered simplj^ as the nutritive vessels 

 of the skin. This is the more probable, as these vessels are very superficial, and 

 onl}' covered b}^ a very thin epidermis. Thej' are indeed as jilainly visible, 

 through the horny la^'er which protects them, as the vessels of any special external 

 breathing organ, and give to the lower surface of the body, over which they 

 extend, a very ornamental appearance. 



Turtles have a voice. Though I have myself made this observation only in 

 a few species, namely, in Emys clegans, serrata, picta, and insculpta, which emit 

 a piping nf)te,^ and in Chelonia Mydas, whose voice reseml:)les somewhat a quick, 

 low bark. I am inclined to believe that all of them have, more or less, the 

 faculty of emitting distinct sounds. Sjihargis has its name even from aqaQuym, to 

 make a noise. But, whether this name is meant o)ily for that sharp hissing sound 

 which all Turtles produce, when the}^ are excited, or v/hether it is intended to 

 designate a real voice, I am not able to state, as I have never heard the soujids 

 emitted by Sphargis. However, it is reported of many Turtles, especially of the 

 Chelonioidffi, that thoy cry aloud when tliey are seriously wounded. 



I have not yet been able to ascertain to Avhat extent the respiration is reduced 

 or interrupted in those Turtles which burrow under the ground diiring the winter. 

 In the more aquatic species, however, Avhich secrete themselves in the mud, under 

 the surface of the water, the pulmonary respiration is, of coiu'se, entirely suspended. 

 The changes, which the other functions imdergo in different families during tliis 

 state of hibernation, have not yet been investigated. It would be easier to make 

 these observations in the Southern States, where the waters remain open all the 

 year round, than in the Northern States, where the ground is covered annually, 

 for several months, by a thick sheet of snow and ice. 



^ Compare Dr. A. Sager's Notes on the Anatomy, '^ Dr. Weiiiland informs me that Emys europiEa 



etc., quoted above, p. 277. is known to produce a similar sound. 



