1. Über Protohydra leucarti Greeff und ihre geographische Verbreitung;Abonyi A.;Tenth Int. Congr. Zool., Budapest,1929
2. On the little bodies seen on Hydra;Agassiz L.;Proc. Boston Soc. nat. Hist.,1850
3. The Hydra of the Calcutta tanks;Annandale N.;J. Asiat. Soc. Beng.,1905
4. Hydra orientalis and its bionomical relations with other invertebrates;Annandale N.;Ibid.,1906
5. Freshwater sponges, hydroids & Polyzoa. By N. Annandale.