LUMBRICUS. 135 
Soon after the first deposit, a very minute, microscopic animalcule, 
was visible in the watch-glass. A consider number appeared then and 
subsequently. The form of these creatures was rather the parallelogram 
flattened, begirt with cilia. Their length three times their breadth ; their 
colours faint dingy yellow ; the body generally opaque, but with lighter 
portions on some specimens. Their motion was rather slow towards 
the end of June, and sometimes a tendency to revolve horizontally 
on the centre of the body as an axis. A deep constriction of the middle 
was seen in several, as if they were about to sunder. 
Under a high magnifier, the cilia distinctly formed a fringe or bor- 
der on the margin. A longitudinal channel occupied much of the body, 
which I was inclined to think commenced by a wide circular orifice, the 
mouth in the very extremity. 
It proved impossible to follow the history of these minute creatures, 
perhaps not equalling the thirtieth part of a line. Nor can I pretend to 
affirm that they were not of the Animalcula infusoria group, fig. 4. 
One specimen survived eighteen months, when it perished acci- 
dentally. 
Pate XVIII. 
Fic. 1. Lumbricus cirratus. 
2. Section of a cirrus. 
3: Ova. 
4. Animalcula. 
§ 6.—LuMBRICUS MARINUS—ARENICOLA PISCATORUM—Luy Worm— 
Plate XIX. 
The inhabitants of the sea-coast, or those who frequent the wet and 
shallow shores of Scotland, cannot avoid remarking certain places almost 
occupied by pyramids or rolls of mud and sand cast up, as the tide conceal- 
ing them recedes. In some quarters these are extremely numerous, of 
unequal size and quantity, in others they are proportionally rare ; but in 
all it is evident that considerable humidity favours their production. 
All these heaps proceed from an animal lurking at a considerable 
