208 Proceedings of the Tioyal Physiccd Society. 



Ivegion on the one hand, and on the other in that of the old 

 Lemuria of Dr Sclater (an hypothetical region, in whose 

 former existence many competent geologists and biologists 

 still believe). From the Lemurian continent or archipelago, 

 in still later times, the crested forms spread to what is now 

 the Oriental Eegion ; and, later still — when the present 

 limits of the Ethiopian Eegion began to be marked out, and 

 Lemuria to be submerged — other forms were extended into 

 Madagascar and Southern Africa. 



How and why the ancestral forms became crested, or 

 retained crests, may long remain a subject for speculation. 

 But I think we may safely conclude that the crests them- 

 selves are, as a feature, older not only than the genera or the 

 sub-families that bear them, but older even than tlie conti- 

 nents — perhaps (as I believe they are) older than some of the 

 oceans. 



XXI. Zoological Notes. By FiiANK E. Beddard, Esq., M.A., 

 E.RS.E., F.Z.S., Prosector to the Zoological Society 

 of London, Lecturer on Biology at Guy's HospitaL 



IL 



Aquatic Earthworms. 



(Read 18th December 1889.) 



It is well known that many of the Oligochaita, which are 

 usually found in ponds and rivers, can also live in damp 

 soil. The Enchytrseidse, for example, appear to contain quite 

 as many terrestrial as aquatic forms ; and even the same 

 species may occur in either habitat. But there are not 

 many instances known of earthworms which lead a partially 

 or entirely aquatic life; indeed the fact that these Annelids 

 have been generally supposed to be entirely terrestrial, has 

 been to some extent the cause of their having been dis- 

 tinguished as a separate group of the 01igocha3ta — Oligochccta 

 Terricolce. So far as I am aware, there is only one species 

 closely allied to Luiiibrieus terrestriSy which has been proved 

 to occur in rivers, as well as in the soil. In a recent number 



