390 Records of the Indian Museum. [Voy. XII, 
refers to the same form as a species of Bithynis, has given the 
following account of its habits.—‘‘ Un Palémonidé du genre Bithy- 
nis Dana mérite une mention spéciale par son habitat et sa colora- 
tion. Il est absolument transparent, mais se signale par quelques 
anneaux d’un violet pale sur les appendices et l’abdomen, et sur- 
tout par des taches d’un blanc nacré éclatant, occupant la région 
stomacale tout entiére, le coude de abdomen, 1’extrémité des 
rames caudales et les épiméres du deuxiéme segment. Ce magni- 
fique Crustacé se tient obstinément dans la zone de protection que 
circonscrit une grande Actinie assez commune dans les flaques 
profondes qui séparent les Madrépores. Etalé sur lesable, le disque 
oral de l’Actinie de couleur blanchatre, armé d’un trés grand 
nombre de courts tentacules urticants, atteint souvent o m. 30 de 
diamétre. Buthynis se tient dans ce cercle, nageant 4 peu de dis- 
tance au-dessus, souvent par couples, et se laisse assez aisément 
capturer a l’aide d’une eprouvette pleine d’eau que l’on descend 
doucement sur l’animal.’’ 
The anemone at Port Blair was one with greenish tentacles, 
not whitish as in Coutiére’s description. It was not uncommon 
at low water on the foreshore at ‘‘ Aberdeen”’ and was sometimes 
left high and dry by the tide. On anemones from which the water 
had completely retreated we failed to find any shrimps, even 
though the whole specimen was dug up and most carefully ex- 
amined. On the other hand the shrimps were seldom absent from 
anemones living in a few inches of water, and were easily caught 
in a tube full of water as described by Coutiére. The Ancylocans' 
was found swimming and crawling on the column of the anemone 
beneath the {fringe of tentacles and wandering occasionally on to 
the disc. Thor discosomatis had similar habits, but seemed to 
wander further afield and rarely ventured among the tentacles. 
The curious feature of the shrimps is that in both species the 
pigmentation takes the form of very large spots almost pure white 
in colour. ‘This, too, is a characteristic of certain fish, Amphiprion 
percula (Lacép.) and Tetrvadrachmum trimaculatum (Ripp.),’ which 
also appear to live commensally with the Discosoma ; the latter was 
found beneath the fringe of tentacles and was black with a broad 
transverse band of white at the back of the head, extending down- 
wards to the eye, and a large white spot below the dorsal fin; the 
former, which was commonly found swimming among the ten- 
tacles, was bright orange with three broad bands of white tinged 
with green and narrowly margined with black. The presence of 
white patches in all four commensal species is a most curious 



! Couticre, in this brief description, has scarcely done justice to the marvel- 
lous colouration of Ancylocaris aberrans; the large white patches are frequently 
circumscribed by red or orange pigment and on the tail-fan are eye-spots with 
reddish centres. A complete account of the colouration of this Palaemonid would 
be out of place in the present paper, but it may be mentioned that the pigmenta- 
tion varies somewhat in the two sexes and alters considerably with age. The 
colouration of Thor discosomatis, on the other hand, is apparently constant 
throughout life. 
2 | am indebted to Dr. B. L. Chaudhuri for these determinations. 
