1910.] ON A ROUNDWORM AND THE INFECTION OF CYCLOPS. 387 



joints or to the Pacchionian bodies in the venous sinuses of the 

 dura mater. 



It was suggested that these pleural venous plexuses were 

 possibly of use in regulating the pressure of the pleural fluid in a 

 manner similar to that in which the pressure of the cerebro-spinal 

 fluid is regulated by the Pacchionian bodies. 



Mr. Frank E. Beddard, M.A., F.R.S., F.Z.S., Prosector to the 

 Society, exhibited a series of specimens of Earthworms from 

 Luzon, Philippine Islands. 



Dr. C. "W. Andrews, F.R.S., F.Z.S., exhibited and made remarks 

 upon some teeth of Elephas [Stegodon) insignis and of a species 

 of horse from China. The former were from Sze-chuen, probably 

 from beds of Lower Pliocene age, and were sent to the British 

 Museum by the Rev. W. C. Taylor, of the China Island Mission. 

 The horse teeth were from Tsi-shan, N. China, from a depth of 

 about 300 feet in the Loess, probably of Pleistocene age ; these 

 were sent by the Rev. R. Gillies, also of the China Inland 

 Mission. 



Dr. R. T. Leiper, F.Z.S., exhibited the larval stage of Tricho- 

 strongylus pergracilis, the causal factor of Grouse disease. He 

 found experimentally that the development follows almost exactly 

 the same course as that of the Ankylostome — the cause of miner's 

 disease in Cornwall. The egg developed into embryos in about 

 two days, and metamorphosed on the eighth day into a peculiarly 

 active larva that climbed heather only in wet weather. These 

 larvae were found in extraordinary numbers on the plants, the 

 roots of which were experimentally infected. Subsequent drying 

 did not kill the larva?, for by encysting they could survive several 

 weeks without additional moisture, but were unable, however, to 

 resist desiccation. They underwent no further developmental 

 change, and this stage, when fed to healthy Grouse, alone was able 

 to produce infection, and within four days eggs were found in the 

 droppings. 



Dr. Leiper also exhibited a specimen of Cyclops containing a 

 living embryo of Cucullanus elegans, a blood -sucking parasite of 

 Perch, and discussed the mode of entry into Cyclops of this worm 

 and the guinea- worm. Experiments showed that the embryos only 

 penetrated living Cyclopidse, and led to the conclusion that the 

 Cyclops actually swallowed the living embryos and that these 

 penetrated the stomach. 



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