LAND AND FRESHWATER MOLLUSCA. 145 
11. Cyrena ceylonica (Chemnitz). 
Venus ceylonica Chemnitz, Conch. Cab. vol. vi. pp. 280, 333, pl. xxxu. fig. 336: Philippi, 
Abbild. vol. 11. p. 108, pl. m1. fig. 3 (Cyrena): Sowerby, Conch. Icon. vol. Xx. pl. XIX. 
fig. 111 (Cyrena). 
Hab. A large freshwater lake, surrounded by mangroves, in the centre of Landu, 
Miladumadulu Atoll?. 
The species of this genus are generally found near the coast, often buried in the mud 
of mangrove-swamps. The single specimen from the above 
locality does not present any characters, which will separate 
it from the Ceylon form. The outline of most species of 
Cyrena is subject to considerable variation, and as the colour 
and sculpture of the periostracum are very similar in many 
of the so-called described species, their identification be- 
comes exceptionally difficult. 
Note ON KALIELLA OR SITALA VAGATA. 

Since I described this species, Colonel Godwin Austen 
has kindly examined the radula. He observes—“<I have 
now come to the conclusion that it is nearer to Kaliella 
\} 4 d 
G ry than any group I know—both in the general form of the 
(ar teeth and formula, 
a 
[) 4 
K. vagata Type of Kaliella 
Fic. 24. 1. Shell. 2. Sculpture of 32-6—-1-6-32 26-7-17-26 
upper surface—growth lines 19 to 381-38 33-1-33 
xiv Of an inch. 3. Spiral lines : : 
on lower surface 9 to ;1,; of an The admedian teeth are all alike, with a long central 
inch. 4. Radula: a. 6th admedian tooth, with large side cusps, on a quadrate basal plate. 
tooth ; b—d laterals, : : : ‘ . 
: The lateral teeth are tricuspid, becoming very minute on 
the margin. The sculpture of the shell is not as in the typical Kaliella, which is finely 
lirate transversely, but the transition to a decussate or papillate surface cannot count for 
much.” 
} [The animal is very rarely found, even in this locality. Maldive Group, the natives elsewhere did not recognize the 
Although similar pools are by no means uncommon in the shell. Ep.] 
19—2 
