Page:Tropical Diseases.djvu/800

features of the cercariæ of S. hæmatobium and S. mansoni. Leiper lays stress on four points, viz.: (1) that these cercariæ

Fig. 133. Bulinus dybowski. (After Leiper.)

Fig. 134. Bulinus innesi. (After Leiper.)

Fig. 135. Bulinus contortus. (After Leiper.)

Fig. 136. Planorbis boissyi. (After Leiper.)

have no pharynx (an adult character); (2) they have forked tails; (3) they have no "eyespots," that is, two minute collections of dark pigment located in the anterior third of the body on either side of the middle line between the suckers—a