80.  Hydrus.

Captain G. Grey informs me that these snakes coil themselves upon the shore, living on the seaweed, and that they lay their eggs on the shore.  They are often found asleep upon the sea, when they are easily caught, as they cannot sink without first throwing themselves on the back, probably to empty their large vesicular lungs.

83.  Platemys macquaria.

This species was originally indicated by Cuvier, from a single specimen brought from the Macquarie River by Messieurs Lesson and Garnot.  It has been doubted if it really is an inhabitant of that country, and might not have been imported from South America, whence all the other species of the genus come, and sold to the French collectors for a native species.

84.  Hydraspis australis, t. 6.

Body ovate, back dark olive, rather convex, rounded on the middle of the sides, with a narrow reflexed edge, shelving behind with a broad expanded margin; vertebral shields broad, six-sided, last subtriangular; beneath rather convex, yellow, shelving on the sides; the second marginal plate with an angular lobe produced into the suture between the vertebral and first costal plates; claws sharp, black; skin of head and limbs smooth.

Inhabits Western Australia ?

The back covered with conferva.

85.  Chelodina longicollis.

Mr. Gould brought two large specimens of this species, which are much more ovate and convex than Dr. Shaw’s specimens.  They are 7 inches long by 6 wide.  It may be a particular variety, or they may become more ovate as they increase in size, The sternal shields (in specimens preserved in brine) are pale yellow, with black edges.

86.  Chelodina oblonga, t. 7.

Shell oblong, rather contracted in front, with a broad impression on the middle of the back; back olive brown, with irregular anastomosing lines on the shields; beneath reddish-yellow.  The marginal plates longer than broad, the second larger than the first and third; and rather angularly produced in the middle of the inner edge, opposite the suture between the first dorsal and first costal plate; the sternum high, flat, strongly and sharply keeled on the sides.

Inhabits Western Australia.

This species is at once known from Chelodina longicollis by the form of its high, flat sternum, which is strongly keeled on the sides, and by this part being of a uniform reddish colour, without any dark margin to the plates; the hinder part of the sternum is only slightly concavely truncated, and not deeply notched.

It is also known from that old well-known species by its oblong depressed form, and by the form of the marginal plates, and especially from the second and eleventh marginal plates on each side being placed more forwards, so that the centre of their inner edge is opposite the suture of the first and last costal plates with the dorsal ones; instead of their front margin, as is the case with all the specimens of Chelodina longicollis I have seen.