174 
The British Leeches 
were still found in Ireland in 184-9. There seems to be no doubt that 
this species is now extinct in the British Islands. 
Fig. 13. Hirudo medicinalis. Diagram of anterior and posterior extremities. Somites 
are numbered in Roman numerals and rings in figures. The 5 pairs of eyes are 
indicated by black dots. 1st pr. neph., 17th pr. neph., position (on ventral surface) 
of first and seventeenth pairs of nephridiopores. an. Anus. (Adapted from 
Whitman.) 
Leeches in Commerce. Although Hirudo medicinalis was known 
to the ancients it was not in great demand for use in phlebotomy until 
the beginning of the nineteenth century. The traffic in medicinal 
leeches soon assumed enormous proportions and reached its zenith in 
France in 1832, in which year, Ebrard tells us, nearly 57-|- millions of 
these annelids were imported into that country. As the natural sources 
of supply failed, the artificial cultivation of leeches in special ponds 
became a profitable industry. For further information on the subject 
