28 7 



i. Fam. CHELYDRIDAE. 



Shell covered with epidermal shields. Head large, incom- 

 pletely retractile; neck completely retractile; chin with small 

 dermal appendages. Plastron small, cruciform, articulating with 

 the carapace by gomphosis; inframarginalia present; nine 

 plastral bones. Nuchal plate with long rib-like processes. Tail 

 long. Digits moderate, with four or five claws. 



A single genus inhabits the Indo-Australian region. 



i. Devisia D. Ogilby. 

 (DOUGLAS OGILBY, Proc. Roy. Soc. Queensland XIX p. n, 1905). 



Head large, depressed, triangular; orbits lateral. No supra- 

 marginal shields. Tail with irregular shields of variable size below. 

 Distribution. New Guinea. 

 A single species. 



i. Devisia mythodes D. Ogilby. 



Devisia mythodes, Douglas Ogilby, Proc. Roy. Soc. Queensland XIX 1905, p. 1 1. 

 Devisia mythodes^ Siebenrock, SB. Akad. Wiss. Wien Vol. 116 1907, p. 532; 

 Zoolog. Jahrb. Supplem. X 1909, p. 435- 



Carapace ovate, depressed in the median line; its greatest 

 width above the inguinal region, anteriorly feebly emarginated, 

 posteriorly slightly serrated. Nuchal shield crescentic, its 

 anterior border with narrow spiniform processes; vertebrals 

 with a few coarse striae, first tetragonal, the others rounded; 

 first costal shield triangular, second largest; supracaudals angu- 

 lated posteriorly. Plastron smooth, width of the bridge i4 J /4 

 times in length of plastron; gular shields small, triangular, 

 basal width less than length; humerals tetragonal, a deep 

 narrow groove extends outwards and backwards, crossing the 

 humero-pectoral suture; pectorals subtetragonal; abdominals 

 hexagonal; femorals pentagonal; anals triangular; anterior and 

 posterior inframarginalia present. Head large, triangular, 

 depressed, with two pair of parietal ridges, the inner pair con- 

 verging and uniting in a prominent point on the posterior 

 border of the occiput. Nostrils small and circular, in a depressed 

 vertical plate; two small supranasals; a pair of large praeoculars, 

 meeting at the median line; supraoculars also meeting; a single 

 postocular; frontal strongly rugose, with its point wedged in 

 between the convergent parietal ridges; parietals broken up 



