280 
PACIFIC SCIENCE, Vol. XV, April 1961 
Figs. 1-4: 1, Adult Mesostepkanus appendiculatus , ventral view; 2, sporocyst; 3, diagram to show most 
of excretory system; 4, cercaria, ventral view. Abbreviations : a, Acetabulum; b, birth pore; c, cirrus sac; e, egg ; 
g, genital primordium; i, Island of Cort; m, metraterm; o, ovary, or oral sucker; p, pharynx; t, testis; tr, tribo- 
cytic organ; v, vitellaria. All drawings made with the aid of a camera lucida unless otherwise stated. 
