TRANSACTIONS OF SECTION D. 761 



water forms, the commonest can he traced to the conversion of marine into fresh- 

 water areas. The earliest known lacustrine areas, those of the Old Red Sandstone, 

 have yielded a species of pond-mussel, which has been described as Anodonta 

 Jukesi by Forbes. The Permo-Triassic lakes contributed additional fresh-water 

 forms, such as the Neritina and Melaniidse ; other genera probably arose at this 

 time, the occurrence of Unio, Physa, Valvata, and Lymnea, in the Nearetic, 

 Palsearctic, and Oriental regions during Cretaceous times suggests for them a high 

 antiquity, possibly reaching into Paleozoic times. 



The lakes of the Tertiary period furnished probably the fresh-water genera 

 Lithoglyphus and Dreissena. 



Thus existing fresh-water genera are probably descended from marine forms 

 which became metamorphosed in the waters of the Devonian, Triassic, and 

 Tertiary lakes. 



4. On a Fish supposed to be of Deep-sea Origin. 

 By the Rev. D. Honeyman, D.C.L., F.B.S.C. 



5. On the Trapping of Young Fish by the Water Weed, Ultricularia Vulgaris. 

 By Professor Moseley, LL.D., F.B.S. 



The fact that the plant thus preys upon vertebvata was discovered by Mr. G. 

 E. Simms, son of a tradesman in Oxford, and communicated to ' Nature ' in a letter- 

 by Professor Moseley, printed in ' Nature ' of May 22, 1884. There appears to be 

 room for much interesting further research as to the action of the plant in the 

 process. Professor Moseley found of one batch of young fish placed in a vessel with 

 a quantity of weed a certain residual number remained untrapped for several 

 weeks. Possibly the plant soon loses its power of trapping when left in confine- 

 ment, or is affected by change of temperature in the weather. The old traps 

 seem possibly less active than the young. Possibly young fish of certain species 

 are from their habits less liable to be trapped than others. The bodies of the dead 

 entrapped fish are rapidly reduced to a glairy mass by swarms of infusoria, which 

 possibly thus prepare the prey for the nourishment of the plant, taking the place- 

 of actual digestive organs, which Mr. Darwin showed to be absent in Utriculariae. 



6. On the Concordance of the Mollusca inhabiting both sides of the North 

 Atlantic and the intermediate Seas. By J. Gwtn Jeffreys, LL.D., 

 F.B.S.—See Reports, p. 531. 



FRIBA Y, A VG VST 29 



The following Reports and Papers were read : — 



1. Fourth Beport of the Committee for the Investigation of the Natural 



History of Timor-Laut. — See Reports, p. 263. 



2. Beport of the Committee for the Exploration of Kilima-njaro and the 

 adjoining Mountains of Eastern Equatorial Africa. — See Reports, p. 271. 



3. Beport of the Committee for arranging for the occupation of a Table at 



the Zoological Station at Naples. — See Reports, p. 252. 



! , . 



4. Beport on the Becord of Zoological Literature. 



