454 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. 



the inside of the tube, that it can turn itself freely about, and move up and 

 down, the better to attack and secure its prey. 



This scolopendra has two very curious and remarkable tentacula, or arms, the 

 left much larger than the right; these are doubly feathered, as may be seen, in 

 the magnified part, at c ; the number of feet on each side of the botly of this 

 animal exceeds 150. 



Plate 10, will best explain the rest; where b is the belly part of the animal, 

 in its natural size, hanging out of its tube, i is the same side of the whole 

 animal a little magnified, a is the back part of the head of the animal, sitting 

 in its tube, h is the back part of the whole animal a little magnified, e shows 

 the inside of the tube with the strata, or rings, seen through the horny inner 

 coat. 



The coralline called (in Ray's Synops. ed. 2, p. 2, and ed. 3, p. 36, N° 15) 

 fruticulus marinus, cauliculis crassiusculis teretibus rigidis, pennatus,* which I 

 have named the herring-bone coralline, and which is very common on oysters 

 all the winter season, shows remarkably, by the help of a common magnifying 

 glass, the tubulary structure, not only of some of the corals and corallines, but 

 of the keratophytons, or sea feather; only with this difference, that the tubes 

 of the herring-bone coralline are of a spongy elastic nature, and always remain 

 open; whereas the others, being of a more soft and viscid nature, by time, and 

 the heat of the climate, are compressed together, and harden, some into stone, 

 and some into horn or wood. 



At E is the natural appearance of the herring-bone coralline; and f and g the 

 root, and one of the upper branches, are magnified, to show the tubes. 



LXJ^. Observations on the late severe Cold Weather. By William Arderoii, 



F.R.S. p. 507. 



The observations were taken by thermometers exposed to the open air, in the 

 garden, which varied sometimes 40 or 50 degrees in 24 hours; the cold coming 

 as it were by fits, in an unusual manner. 



Dec. 30, at 1 1 o'clock at night. — All the spirits in Hauksbee's thermometer 

 retired into the ball, and Fahrenheit's stood at 20 degrees: at this time he let 

 down a Fahrenheit's thermometer into the river, to the depth of 4 feet, during 

 12 minutes, and when taken up it stood at 33 degrees. 



This same evening he exposed an open glass jar full of water, in the garden, 

 to be frozen; and in the morning it was all solid ice, rising in the middle, in fi- 

 gure like the frustum of a cone. He exposed also, in the same place, an open 

 glass of ale, which froze even to the bottom, in a very odd manner; for the 



• Sertularia haUcina. Linn. 



