22 THE HANCOCK PACIFIC EXPEDITIONS VOL.2 



EXPLANATION OF PLATE 2 



All figures were drawn with the aid of a camera lucida. The projected scale 

 has the value (in mms.) indicated for each figure. Abbreviations: ac, acetabulum; 

 ce, intestinal cecum; ex, excretory vesicle; gp, genital pore; gs, genital sinus; /, lym- 

 phatic vessel; pp, pars prostatica; sr, seminal receptacle; sv, seminal vesicle; ut, 

 uterus. 



Fig. L Apocreadium mexicaimm. Dorsal view. 



Fig. 2. A. mexkanum. Frontal section through posterior half of the body, 

 showing the branching lymphatic vessels. 



Fig. 3. A. mexicanum. Cross-section through the region of the seminal re- 

 ceptacle. 



Fig. 4. A. longisinosum. Ventral view. 



Fig. 5. A. longisinosum. Terminal reproductive organs. 



Fig. 6. A. longisinosum. Cross-section through anterior portion of the 

 pharynx. 



Fig. 7. A. longisinosum. Portion of two lymphatic vessels showing lympho- 

 cytes. 



