308 APPENOIX. 



mentioned. Dr. J. R. Johnson says, that it will swallow almost 

 anything presented to it. 



In the writings of medical authors there is much said of the danger 

 of swallowing leeches, — one would imagine not a likely accident, nor 

 did I ever hear of one that could be authenticated. I find in the 

 " Daily News" for March 19, 1847, the following paragraph : — " A 

 farmer in Ruthwell, Dumfriesshire, lost about half a score of sheep 

 lately, and on examination being made of the cause of death, it was 

 discovered that the intestines contained a number of loch or horse 

 leeches. These animals had probably been swallowed by the sheep 

 when drinking, and appeared to have eaten through the coats of the 

 stomach, until they reached a vital part, whereby death was pro- 

 duced. Mortality among sheep has been very prevalent in this 

 district; one farmer in the neighbourhood of Annan has lost 40 

 sheep, and another 30 this season." 



When fully extended the horse-leech is about 4 inches in length, 

 linear-oblong, a little narrower in front, flattened, of a uniform dark 

 olive-green colour, or almost black, the ventral surface a yellowish- 

 green. The body consists of numerous narrow rings which render 

 the margins crenulate. The head is rounded, but not dilated ; and 

 on the vertex there are ten eyes arranged in a semicircle : the ante- 

 rior pair are larger than the others and more approximated, and the 

 posterior pair are placed rather wide asunder, thus : — 

 The mouth has a strong muscular plicated gullet with . '. 

 three small cartilaginous teeth, forming as it were sum- ; \ 

 mits to as many of the plaits. The anal sucker is cir- 

 cular and entire. 



There are a few black spots both on the back and belly, but they 

 are very irregular, and sometimes obscure or wanting. In some 

 individuals the ventral surface is scarcely different in colour from the 

 dorsal, and in these a pale yellowish line marks the edge of the body. 

 The leech seems always on the look-out to escape from its confine- 

 ment in water ; and it is oftenest found under stones just above the 

 water-line of its pond. It moves by stretching the body to the 

 utmost from the anal sucker by which it has anchored itself, attaching 

 the mouth, and then dragging the body onwards, without raising it 

 much above the surface. It swims with grace and ease in the water 

 like an eel. It exudes a sparing quantity of a whitish mucus. On 

 being immersed in spirits the belly becomes of a much brighter yel- 

 lowish-green, but it does not tincture the fluid. 



" This is an active, bold, and clever animal, frequently crawling 

 out of the water, and apparently always ready to quit its vessel. 

 None of the tribe surpasses it in voracity. Few animal substances 

 are rejected. All kinds of fish, dead or alive, seem acceptable. 

 Penetrating the cavity of the larger freshwater shells, the horse-leech 

 takes up a permanent dwelling there, until emptying them of their 

 contents, should it be able. Several of this and the preceding spe- 

 cies, the octocu/ata, having been collected from the same place, one 

 of the latter, half-swallowed by a horse-leech scarcely double its size, 

 was discovered struggling for liberty. But its ferocious enemy, 



