118 SoLttas— On the Origin of Freshwater Kaunas. 
Norse I.—Since this Paper was in type, Professor Ray Lankester has kindly 
called my attention to some observations by Dr. J. Von Kennel,* who describes 
certain lagoons bordering the coast of Trinidad, which communicate at times with 
the sea, and so receive a number of marine inhabitants; and when subsequently 
the water of the lagoon becomes fresh, several of the marine forms, adapting 
themselves to the changed conditions, continue to live on, and amongst others 
thus persisting is a Medusa, which Dr. Kennel regards as different from Limnoco- 
dium, without, however, specifically determining it. 
Besides this repetition by Nature of Beudant’s experiments, Dr. Kennel gives 
a very clear instance of the direct introduction of marine forms into a river—due 
probably to the transportation of free-swimming larve by tidal agency—thus, he 
mentions Mytilaceze, a small species of Pholas, and Lumbriconereis, as existing in 
the freshwater of the river Ortoire, eight miles above its mouth. 
Nore IJ.—The occurrence as freshwater forms of marine animals which 
inhabit floating timber is very suggestive from two points of view, for first it 
leads one to infer that, in such cases, means of transport bemg afforded, adapta- 
tion to freshwater conditions follows readily ; and next, since such instances are 
rare, that to inhabit freshwater is only the first step towards becoming a 
characteristic freshwater organism; till the developmental history also becomes 
modified a wide distribution is not probable. Hence I would call special attention 
to Prof. E. Perceval Wright’s remarks on this subject in a Paper describing a 
freshwater Teredo (Vausttora Dunlope:) in the waters of the river Hurreegonga a 
tributary of the Ganges.T 
* Biologische u. faunistische Notizen aus Trinidad, Arb. d. Zool.-zoot. Instituts in Wurzburg; Bd. 
vi., 1883. 
+ On a new genus of Teredinine, by E. Perceval Wright, u.p., Transactions Linnean Society, Vol. 
xxvi., p. 451 (1864). 
