210 CHELYDIDJE. 



Caxapace with three series of large nodose protuberances or keela, 

 the shields very rugose, with strong radiating striao ; posterior 

 margin more or loss strongly serrated ; vertebral shields broader 

 than long, about as broad as costals. Plastron subcruciform, front 

 lobe rounded, broader than the hind lobe, which is deeply notched ; 

 plastral shields very variable in shape, femorals constantly the 

 longest ; intergular either small and separating the gulars only 

 anteriorly, or large and widely separating the latter shields ; axillary 

 and inguinal shields indistinct. Head extremely depressed, trian- 

 gular, covered with small warts or granules. Limbs with small 

 scales, the largest of which are crescentic. Brown ; young elegantly 

 marked with brown and yellow bands along the chin and neck, and 

 with black and yellow spots on the shell. 



Length of shell 38 centim. 



Guianas, Northern Brazil. 



a. i'g., spir. - Cayenne. 



h. § , stffd. Cayenne. 



c,d. S, stffd. Brazil. 



e. Yg., spir. Manaos, Brazil. M. A. Peixoto [C], 



/, g. Ad., skels. ? 



"/i.Eggs, laid in the Zoological Gardens, London. 



2. HYDROMEDUSA. 



Chelodina, part., Fitzing. K Class. Rept. p. 6 (182G) : Diim. ^- Bihr. 



ii. p. 441 (1880). 

 Ilydromedusa, Waglcr, Syst. Amph. p. 135 (1830); Gj-aj/, Cat. Tort. 



p. 43 (1844), and Sh. Rept. i. p. 59 (1855) ; Sf ranch, Chelun. Sfiul. 



p. 47 (1862) ; Gray, Snppl. Cat. Sh. Rept. i. p. 73 (1870); Gitnth. 



Ami. ^- Mag. N. H. (5) xiv. p. 422 (1884). 

 Hvdraspis, part., Gray, Si/n. Rept. p. 39 (1831). 

 Chelomedusa, Gray, Ami. Sf May. N. II. (4) xi. p. ,303 (1873). 



Neural plates present, seven in number, the last pair of costate 

 forming a suture ; nuchal shield present, situated behind the anterior 

 marginals, simulating a sixth vertebral ; plastron large, with mode- 

 rately strong axillary and feeble inguinal buttresses, the latter just 

 reaching the fourth costal plate. Neck longer than the dorsal ver- 

 tebral column. A slender supraoccipital arch ; jaws weak, without 

 alveolar ridges ; a strong fold at the angle of the mouth, connecting 

 both jaws. No dermal a2)pendages on the chin. Both pairs of limbs 

 with four claws ; digits entirely webbed. 



South America. 



1. Hydromediisa maximiliani. 



Emys maximiliani, Mikan, Delect. Flur. et Faun. Rra.i. pi. 



(1820). 

 Chelodina maximihani, Fitzing. N. Class. Rept. p. 45 (182G). 

 llydraspis maximiliani, Gray, Syn. Rept. p. 43 (1831). 



