72 The Hydra of the Calcutta Tanks. { March, 1905, 
6. The Hydra of the Calcutta tora ttle ANNANDALE, 
B.A. — Superintendent of the Indian Museum 
individual. Coloration Tentacles and base milky white; distal 
portion of the body either pale or dark olive- aie deep chestnut, 
lens i pets pale brown, cream-colour or dirty white; never 
bright gree 
_ When x exhibited specimens of the Calcutta Polyp to the 
Society I was inclined to ee Es at most as a variety of Hydra 
viridis, using the specific nam more extended sense than 
its author Linneus ado pted, oe ends H. fusca. A careful 
study of the roieea of the European forms and an examina- 
tion of a larger nnmber of Indian specimens has since led me to doubt 
whether I was ae im coming to a decision I am indebted to a 
of Edinburgh, setts has not, however, seen the Indian form. On the 
whole this form appears to be rela ted to Pallas’ H. vulgaris ; but 
variable in appearance from moment to moment, is a very difficult 
one. From typical specimens of H. calgon it differs in several 
important details. 
en the animal is clinging to an inclined or vertical surface 
the expanded “ieniecien are arched, their proximal portion project- 
ing in a straight line from the disk, while the distal extremity 
either falls downwards or extends upwards tv) 
lo ay be found in the same tank, but the darker speci- 
m: mon over deeper water. Specimens kept 1 
~~ light fade so as to become of ana e orm 
een. 
e Polyp is usually found on the nee surface of the 
floating leaves of water-plants. It is by no means uncommon 
but may be a little hard to find. Sexual reproduction takes 
place at any rate from December to March, but probably 
1 T have just seen petals % en poet wana y of what 1s 
Hy e Spe aegee of 
Hydra. (Zool. J Jahrb., - Anat 1905 ). He 6 seeomuiaes, on oe suffi- 
cient grounds, ~ following fonr, with one variety of the first :—(1) i. parse 
Linn. ; (2) H. grisea, Linn. (with H. weet Pall., as a synonym); ( 
inn, ; heect, wnin sex r 
objection is that a specimen which it is desirable to identify may not be breed- 
ing—then the Indian Hydra should be regarded as a distinct pict though 
it may only be protandrous or the converse. Under ‘a circumstances it 
will be convenient to give it, at any rate pitta: specific rank, calling it 
4. orientalis. The description above is a sufficient diagnosis. Jane 6th, 1903. 
