154 Records of the Indian Museum. [Pp More Vag 
1. Dogania subplana (Geofir.). 
Boulenger, Fauna, p. 9. 
DIstRIBUTION.—Arrakan, ‘Tenasserim, Mergui Archipelago, 
the Malay Peninsula, Sumatra, Java, Borneo, and the Philippines. 
SPECIMENS :— 
BURMA. 
11589 (spirit): juv. .. Tibu, King I., Mergui .. Dr J. Anderson. 
Archipelago. 
13468-g (stuffed) : juv. - e Re = 
661 (spirit): juv. .. “‘SinkepI., off E.Coast .. J. Wood-Mason. 
of Sumatra” 
The two specimens in spirit are very young; their colora- 
tion has been obscured by fading but six rather small ocelli 
can still be distinguished on the disk, while the head and neck 
bear traces of longitudinal markings. The stuffed specimens from 
Mergui are probably half-grown, the disk measuring about 23°6 cm. 
in length. These and the young individual in spirit from the 
same district are referred to by Dr. Anderson in his ‘‘ Fauna of 
the Mergui’’ (Jour. Linn. Soc. Zool., xxl, p. 342). 
Mr. H. C. Robinson informs me that this is a purely estuarine 
and marine species. 
Genus TRIONYX, Geoffr. (1809). 
Boulenger, Fauna, p. 10 (fartim): Siebenrock, p. 595. 
This genus, which is by far the largest in the family and 
occurs in the warmer parts of all the continents except Europe, 
is well represented in the Indian fauna, to which at least eight 
species can be assigned. 
The species are difficult to recognize, unless cranial and 
skeletal characters are considered as well as coloration. The 
lower jaw in particular affords diagnostic features of great impor- 
tance in most species. 
The branchial skeleton of this genus is less fully ossified 
and less complex than in some genera of the family. I have 
been able to find specific differences in it in some species. The 
basal part consists in the adult of three pairs of bones, a pair 
of basihyals in front, followed by two pairs of basibranchials. 
The basihyals are widely separated by a cartilaginous plate in 
which small irregular ossifications sometimes occur; their external 
margins are somewhat protuberant anteriorly but do not form 
regular horns. The basibranchials are in close contact in the 
middle line; the large cornua are articulated to prominent 
condyles situated on their external margins. The hypobranchials 
are well developed. They are articulated to the posterior border 
of the posterior basibranchials. The ceratobranchials and pterygo- 
branchials are sometimes represented by cartilage, sometimes 
ossified. 
