210 CHELYDID®. 
Carapace with three series of large nodose protuberances or keels, 
the shields very rugose, with strong radiating strive; posterior 
margin more or less 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. Yg., spir. Cayenne. 
b. Q, stfid. Cayenne. 
c,d. 6, stfid. Brazil. 
e. Yg., spir. Manaos, Brazil. M. A. Peixoto [C.]. 
9 
‘h. Eggs, laid in the Zoological Gardens, London. 
2. HYDROMEDUSA. 
Chelodina, part., Fvtzing. N. Class. Rept. p. 6 (1826) ; Dum. § Bibr. 
ii. p. 441 (1835). 
Hydromedusa, Wagler, Syst. Amph. p. 185 (1880); Gray, Cat. Tort. 
p- 48 (1844), and Sh. Rept.i. p. 59 (1855) ; Strauch, Chelon. Stud. 
p. 47 (1862); Gray, Suppl. Cat. Sh. Rept. i. p. 73 (1870); Giinth. 
Ann. § Mag. N. H. (5) xiv. p. 422 (1884). 
Hydraspis, part., Gray, Syn. Rept. p. 89 (1851). 
Chelomedusa, Gray, Ann. § Mag. N. H. (4) xi. p. 803 (1878). 
Neural plates present, seven in number, the last pair of costal 
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 appendages on the chin. Both pairs of limbs 
with four claws; digits entirely webbed. 
South America. 
1. Hydromedusa maximiliani. 
Emys maximiliani, Mekan, Delect. Flor. et Faun. Bras. pl. — 
(1820). 
Chelodina maximiliani, Fitzing. N. Class. Rept. p. 45 (1826). 
Hydraspis maximiliani, Gray, Syn, Rept. p. 43 (1881). 
