HERPETOLOGY OF JAPAN. 531 



[DOGANIA SUBPLANA" ( Geoffroy-Saint-Hilaire).] 



1809. Trionyx suhplumis Geoffroy-Saixt-Hilaire, Nouv. Bull. Soc. Philom. 

 Paris, I, No. 22, July 1809, p. 3()6; Ann. Mus. Hist. Nat. Paris, XIV, 1809, 

 p. 11, pi. V, fig. 2 (type-locality "unknown"). — Boettger, Offenbach. 

 Ver. Naturk. 24-25 Ber., 1885, p. 135. — Boulenger, Cat. Chel. Brit. 

 ]\Ius. , 1889, p. 24() (Malay Peninsula, Sumatra, Borneo, Java). — Flower, 

 Proc. Zool. Soc. London, 1899, p. 619, pi. xxxvi (Penang; Singapore). — 

 Siebenrock, Sitz. Ber. Akad. Wiss. Wien, Math.-Naturw. CL, XCI, 1902, 

 p. 817, fig. 2 (plastron). — Dogania subplana Gray, Cat. Tortois. Brit. Mus., 

 1844, p. 49; Cat. Shield Kept. Mus., 1855, p. 69, pi. xxxm ("Japan"); 

 Proc. Zool. Soc. London, 1862, p. 265 (China, Formosa); 1873, p. 57, 

 fig. 3 (mandible); Ann. Mag. Nat. Hist. (3), XII, 1863, p. 158. 



There being no specimen of this species at hand from the territory 

 covered in this work, I append l)elow the chagnosis given by Boulen- 

 ger in his Catalogue of Chelonians in British Museum, pp. 246-247. 



Diagnosis. — Carapace very flat; costal plates eight pairs, the 

 last well developed and separated by the last neural plate; a single 

 neural between the first pair of costals; these plates ver}^ fineW 

 granulate and vermiculate; a large fontanelle, till late in life, between 

 the nuchal and dorsal plates; epiplastra narrowly separated from 

 each other in front of the entoplastron, whicli forms an obtuse or a 

 right angle; plastral rugosities scarcely developed, on the hyo-and 

 hypoplastra and on the xiphiplastra ; dorsal skin of young with. 

 interupted longitudinal ridges; head very large; snout (on the skull) 

 about as long as the thameter of the orbit, which is more than double 

 the interorbital width; postorbital arch extremely narrow, forming a 

 keel on its outer surface ; mandibular symphysis shorter than the 

 diameter of the orbit, without median ridge. Brown above, yel- 

 lo^^'ish beneath, and on the sides of the neck; head and neck with 

 yellowish dots; some young with an oblique dark streak behind 

 each eye. 



Length of dorsal disk 25 centimeters. 



Doctor Siebenrock describes the plastral arrangement of this 

 species as follows (op. cit., pp. 817-819): Entoplastron forms an 

 obtuse angle; epiplastra separated, the anterior straight arm as 

 long as the posterior oblique one ; not a trace of a median process of 

 the hypoplastron, so that an undi\aded membranous fontanelle is 

 formed between the entoplastron and the hyo-, hypo- and xiphi- 

 plastra. The plastron of this species is distinguished thereby from 

 that of all other species of Trionyx [Amyda]. The absence of the 

 median process is a very significant character for tlie determina- 

 tion of this species. Xiphiplastra with short and narrow posterior 

 angles which are separated by a rather ])r()ad interspace; xiphi- 

 plastral commissure short, on both sides connected by two teeth. 



a Signifying somewhat flat. 



