THE MEDICINAL LEECH 



19 



Muscles 



The muscles of Hirudo are made up of elongated fusiform cells 

 having an outer contractile myoplasm and an inner sarcoplasm. 

 Immediately beneath the dermis lies a layer of circular muscle 

 fibres, and beneath this again is a layer of obUque muscles, the 



Sense bud - 



Blood cap 



Nerve t 



Epidermis 



Optic cell 



Pigment cup 



Muscle 



erve 



0-2 mm 



Fig. 10. Vertical section through an eye of Hirudo showing 

 also a group of epidermal sense cells. After Hesse, 1897. 



cells of which run at about 45° to the longitudinal axis of the body, 

 right and left. Further towards the centre lies a thick layer of 

 longitudinal muscle cells. Finally there are dorso-ventral bundles 



