Meteorological Observations. 439 



phosis, or become the prey of birds, fishes, frogs, &c. Other Cer- 

 carice pass directly from the body of the mollusk into that of the 

 bird, &c. These metamorphoses, taking place consequently in the 

 bodies of animals belonging to the principal types of the animal 

 kingdom, furnish the most evident proof against the old opinion, that 

 the parasitic worm could only exist within the animal for which it 

 was formed. On the contrary, the preceding facts appear to prove 

 to us, that the migrations of worms through various organisms are a 

 necessary condition of their normal development. Classification will 

 necessarily be much affected by these observations. Many species 

 and genera will be suppressed. Thus it has been discovered quite 

 recently, that a worm belonging to the family of Polystomatay the 

 genus Gyriodactylus, which is found on the branchiae of many fresh- 

 water fishes, is only a transitory form which propagates by gemma- 

 tion. In the interior of this worm, which possesses all the organs of 

 the adult Trematoda, a young one is developed by gemmation, which 

 nearly attains the size of its mother, and finally passes out by an 

 opening on the abdominal side of the latter. "Whilst it still remains 

 within the body of its mother, it forms, by gemmation, a second 

 young one within its own body ; so that in these worms, the mother, 

 frequently contains at once her daughter and grand-daughter. — Bihl, 

 Univ. de Geneve^ December 1851, p. 347. 



METEOROLOGICAL OBSERVATIONS FOR MARCH 1852. 



' Chiswick. — March 1. Fine. 2. Overcast : fine : clear, with sharp frost. 3. Clear 

 and frosty : fine : sharp frost at night. 4. Very fine : clear : severe frost at night. 

 5. Frosty : bright sun : frosty. 6. SUght haze : clear. 7. Frosty, with haze : 

 fine : slight haze. 8. Uniform haze : overcast, 9. Cold dry haze : fine : clear. 

 10. Hazy: foggy at night. 11. Hazy: densely overcast. 12. Cloudy: clear. 

 13. Flying haze : cold and dry. 14. Uniformly overcast. 15. Foggy : dusky haze. 

 16. Slight drizzle : cloudy. 17, 18. Cloudy and cold. 19. Cold haze : white 

 clouds: clear and frosty. 20. Clear and fine : frosty. 21,22. Fine. 23. Slight 

 haze : fine : clear : frosty. 24. Overcast : densely clouded. 25. Clear : overcast. 

 26. Clear : cloudy : frosty. 27. Frosty : cloudy : clear. 28. Overcast. 29. Hazy : 

 fine: rain. 30, Rain: cloudy and mild : overcast. 31. Uniform haze: overcast 

 and cold : cloudy. 



Mean temperature of the month 36°"92 



vt Mean temperature of March 1851 41*72 



Mean temperature of March for the last twenty-six years ... 42 "52 



Average amount of rain in March 1*40 inch, 



Boston. — March 1. Fine. 2. Cloudy. 3. Fine : snow a.m. and p.m. 4 — 7. Fine. 

 8, 9. Cloudy. 10. Foggy. 11. Cloudy. 12. Fine. 13. Cloudy. 14. Cloudy : rain 

 A.M. 15. Cloudy : rain P.M. 16, 17. Cloudy. 18. Fine. 19. Cloudy. 20— 26. Fine. 

 27,28. Cloudy. 29. Fine. 30. Cloudy : rain early a.m. and p.m. 31. Cloudy. 

 Sandwick Manse, Orkney, — March 1. Snow-showers. 2. Snow-showers : snow. 

 3. Snow: fine. 4. Snow: fine: light halo. 5. Thaw: clear: fine. 6. Fine: 

 clear : fine. 7. Fine : hazy. 8. Fog: fine: fog. 9. Fog. 10 — 15. Hazy : fine. 

 16. Drops : hazy : fine. 17. Hazy : fine : cloudy: fine. 18. Bright : fine : cloudy : 

 fine. 19 — 21. Bright : fine: clear : cloudy : aurora. 22. Cloudy : fine. 23. Fog : 

 cloudy. 24. Bright : cloudy. 25. Hail-showers. 26. Hail-showers : snow- 

 showers. 27. Snow-showers. 28. Snow : bright : snow : clear. 29. Cloudy : 

 snow-showers. 30. Bright : clear. 31. Cloudy. — This month has been remark- 

 ably fine and dry, with a high barometer and thermometer. The average quantity 

 of rain in March for six previous years was 255, and in one month only was the 

 quantity smaller, viz. Sept. 1846, when it was only -60. The average temperature 

 of March for twenty-six previous years 40°"38. The average state of the baro- 

 meter has not been higher since May 1844, when it was 30*213. 



