The Sea Lamprey. 411 



and the thermometer experienced considerable oscillations. 

 M. Duprez, commenting on this alarming visitation, states that 

 fourteen out of twenty-two cases of buildings being struck 

 resulted in fires, and that the only edifice which was provided 

 with a lightning-conductor suffered no damage. M. Quetelet 

 adds that, in his statistics of buildings or vessels struck by 

 lightning, he found that out of a hundred and sixty-eight cases 

 in which lightning-conductors had been struck, only twenty- 

 seven, by reason of grave defects in their formation, had failed 

 to exercise a preservative power. 



The average annual allowance of thunder-storms for Bel- 

 gium is fifteen or sixteen, and they are twenty-one times more 

 numerous in summer than in winter. The annual number for 

 a particular locality will vary considerably, being four times as 

 many in some years as in others, while fifteen or twenty leagues- 

 away, the average has not been changed. In our northern 

 countries winter storms, while the sun is below the equator, 

 are usually formed between the clouds and the earth ; those in 

 summer, when the sun is above the equator, are formed in a 

 higher region between the clouds and the stationary layer of 

 the atmosphere, and they have less tendency to strike elevated, 

 objects. Their region of action is often very limited, extending* 

 over only a few leagues. The velocity of the movement of 

 thunder-storms equals that of the most rapid winds. 



THE SEA LAMPREY 



(Petromyzon marinus) . 



BY JONATHAN COUCH, F.L.S. 

 (With a Coloured Plate.) 



The large Sea Lamprey is one of the most remarkable of fishes,, 

 both as regards its organization and habits; and as sucLl, 

 without appearing to have done so, it has obtained special 

 notice, as well among the ancients as moderns. But as actual 

 and close observance of the forms of the inhabitants of the 

 ocean for the purpose of scientific distinction was not much 

 practised in ancient times, some curious mistakes were com- 

 mitted about it by writers of remote date ; most of whom, at 

 least those whose works have come down to us, must have 

 written from the imperfect information which they had gathered 

 from common sources ; and in doing this they appear to have 

 felt the greater readiness to receive it in the proportion that it 

 was strange and mysterious. 



It was commonly believed that there was a fish called the 



