135 231 
The specimens taken in the Gulf of Siam vary considerably in regard to 
colour-ornamentation. Some are quite white, others white with a few brown spots, 
or with one or two broken-off brown rays, or with brown zigzag lines, ete. 
Circe lirata, Romer. 
(Pl. IV, Figs. 28—31). 
Venus (Circe) lirata, ROMER, Monogr. d. Molluskengatt. Venus, I, 1869, p. 208, pl. 59, fig. 2. 
Koh Kahdat, 1 fathom, sand (20). 
Long. 7—24 mm. 
Long. 24 mm., alt. 225 mm., crass. 11°55 mm. 
Distribution: — “Mare chinense” (ROMER). ; 
The specimens from the Gulf of Siam correspond fairly well with Rémer’s 
description; the concentric, raised striz are not so regular and prominent as shown 
in Romer’s figure. The individuals vary greatly in regard to the coloration, and 
of the 20 specimens scarcely two are similar. The scale of colour graduates from 
quite white, to white with a few small brown spots, or with brown rays, or with 
larger scattered brown spots, to almost entirely brown. In individuals measuring 
as much as 16 mm. the whole shell is seen to be covered with the peculiar radiating 
sculpture which is characteristic of the species. The later growth of the shell 
is smoother, especially towards the ventral side. The great prominence of the 
umbonal region is very characteristic of this form. Gafrarium navigatum, Hedley, 
from Mast Head Reef (Queensland),! is no doubt only a young individual of Circe 
lirata, Romer, or another closely allied form. 
Circe nana, Melvy. 
Circe nana, Metyitt, Memoirs and Proce. of the Manchester Liter. and Philos. Soc., vol. 42, 1898, No. 4, 
p. 31, pl. 2, fig. 9: 
-- = = Proc. Zool. Soc. London, 1906, p. 831. 
Between Koh Kut and Koh Kahdat, 10 fathoms, shells (*/2). “Gulf of Siam” (*/2). 
Long. 6—7°5 mm. 
Distribution: — Indian Ocean (long. 26° 10'N., lat. 52° 50’ E.). 
The figure which Metvitt gives of this species shows but imperfectly the 
beautiful sculpture which is produced by the fact that the grooves, which radiate from 
the umbo, turn off on either side and cross the fine concentric lire; but at the 
middle of the valves only the concentric striation is usually present. 
Circe Melvilli n. sp. 
(Pl. IV, Figs. 32—33). 
This little species is roundly triangular in form, milky white, and rather 
convex; the umbo is situated at about the middle, but in some specimens slightly 
1 Proc. Linnean Soc. New South Wales, vol. 31, 1906, p. 476, pl. 38, fig. 33. 
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