INTERCELLULAR RELATIONS OF PROTOPLASTS. 
105 
the great swelling of the thickening substance and obliteration 
of its clearly marked outlines. This thickening substance is 
the callus. The walls thus thickened are perforated by the 
canals of the sieve pores, the pores being , distributed over a 
limited area. Most commonly, markedly in very oblique 
sieve 'plates, a number of such areas are side by side, 
separated by narrow bands of unmodified cell-wall. When, 
on the other hand, the cells composing the tube join by 
nearly horizontal ends, the whole end wall forms a single 
area (or, according to Janczewski, it, in Yitis, frequently 
consists of a number of areas).* This condition is the normal 
one in the great horizontal or but slightly oblique sieve plates 
of Cucurbitaceae (Plate III., fig. 1), in AEsculus , Acer, etc. 
(To be continued.) 
THE HERON (ARTEA CINEREA). 
BY T. V. HODGSON. 
The progress of agriculture has made itself severely felt 
on the majority of birds, but no order has suffered so much 
as the Herodii. Several species of this order were formerly 
common in Britain, and some, in days of yore, considered 
the noblest quarry of the falconer, a sport which has now 
fallen into disuse though still occasionally followed. 
The large tracts of marsh land reclaimed and cultivated 
in these more modern days has driven nearly the whole of 
this order from our shores, and what agriculture has spared 
the gun remorselessly exterminates. The Broads of Norfolk 
and Fens of Lincolnshire form almost the only homes of any 
space left to these birds, and the former are infested with 
gunners, ever ready to slaughter some uncommon bird; 
consequently few of these birds are seen, and those merely 
stragglers from a foreign country. One species, and only 
one, the Heron, seems to have made a comparatively success¬ 
ful struggle against extermination, though constant persecu¬ 
tion has rendered it a veiy wary and a local bird. 
The existence of a small Heronry at Middleton, four 
miles from Tamwortli, has given me a good opportunity of 
watching these birds, and I have endeavoured to make use of 
it, obtaining many a pleasurable hour thereby. The Heronry 
is not more than two hundred yards from the Hall, and 
occupies one end of a wood intersected by a cart-track and 
* Wilhelm (l.c.) thinks this occurs but rarely. 
