MARINE CRUSTACEANS. 201 
says that the propodite of the last leg has its hinder edge smooth. It is not serrate, but 
it bears 4 or 5 minute curved spines, indicated in de Haan’s figure of the female. 
The species was dredged in depths of more than 28 fathoms, on bottoms of sand and 
mud, in Haddumati, Kolumadulu, and Mulaku. 
Genus Thalamita Latr., 1829. 
6. Thalamita prymna (Hbst.), 1803. 
Var. picta Stimps., 1859. Alcock, Iv. p. 79. 
Found sheltering in a coral mass on the outer reef at Minikoi. 
Var. danae Stimps., 1859. Alcock, Iv. p. 77. 
Taken on the reef at Minikoi. 
It would be interesting to know the difference between the habits of this species and 
those of the equally common and somewhat similarly built, though quite distinct, 7. admeta. 
I am under the impression, though the loss of my Minikoi specimens leaves me somewhat 
in doubt on this point, that 7. prymna is a reef crab of a darker, more greenish hue 
than 7. admeta, generally found in the neighbourhood of living corals, and perhaps of rather 
more sluggish habits than the latter. 7. admeta on the other hand, though also found on 
the reef, is, I fancy, a lagoon crab of a paler colour, sometimes almost white, fond of 
lying on the sand, and of extremely active habits. 
7. Thalamita sima H. M. Edw., 1834. Alcock, Iv. p. 81. 
There is considerable variation in the depth of the frontal cleft of this species, and 
same also in the granulation of the under side of the hand. A few specimens came near 
T. poissoni. The absence of spines from the hinder edge of the meropodite is, however, 
always to be relied on as a distinction between the two. The var. granosimana of T. admeta 
tends to approach this species, as will be stated later. 
Specimens were dredged in Haddumati, Nilandu, Kolumadulu, Suvadiva, Fadifolu, 
Felidu, and Mahlos on every kind of bottom below 19 fathoms. Elsewhere it appears 
generally to have been taken as a shore form. Possibly its small size may have caused it 
to escape collection on the shore in the Maldives. On its absence from Minikoi no stress 
can be laid, for the reasons stated in a footnote to p. 191. In dredging, the liability of 
a swimming crab to capture depends, not on its conspicuousness, but on its powers of 
swimming, which are usually greater in larger crabs. The small average size of dredged 
specimens of many swimming crabs is probably due to this. 
8. Thalamita poissoni Aud. and Sav., 1825. Alcock, Iv. p. 81. 
The hands of the female (and to a less extent the small hand of the male) have well-marked 
ridges on the outside and are not full but narrow, like those of 7. admeta, var. savignyi. 
One male specimen from Suvadiva has the spines on the fore edge of the meropodite of 
the cheliped blunt, as they are said to be in YZ. chaptali. The shape of the frontal lobes 
and of the frontal notch varies considerably, and some specimens can hardly be told from 
T. admeta, var. savignyi, when young, or from var. edwardsi of the same species when full 
grown. In other cases there are traces of scaly markings on the under side of the chelipeds 
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