286 University of California Publications in Zoology [Vol. 19 



Dimensions of Margeana californiensis, in Millimeters 



12 3 4 5 



Length of individual 2.41 3 2 2.9 1.9 



Length of oral sucker 0.28 0.31 0.26 0.31 0.24 



Width of oral sucker 0.32 0.41 0.29 0.36 0.26 



Diameter of ventral sucker 0.17 0.19 0.17 0.20 0.14 



From this table it is seen that the proportions of the ventral sucker 

 to the oral sucker vary from 1:2 to 2:3. The measurements of this 

 table are all taken from sexually mature individuals and give some 

 idea of the amount of contraction of the body and suckers in preserved 

 specimens. 



The parts of the digestive system are shown in figure 1. The 

 mouth (fig. 1, m.) is sub-terminal, and the oral sucker (o.s.) is sep- 

 arated from the pharynx (ph.) by a short prepharynx (pph.). The 

 pharynx (ph.) is large, having a diameter of more than half that 

 of the oral sucker. The oesophagus (oes.) is short, being very difficult 

 to make out in toto mounts and the intestinal caeca (i.) extend almost 

 to the posterior end of the body. The intestinal caeca always extend as 

 far back as the posterior fifth of the body and sometimes into the 

 last tenth of the body length, although in the sexually mature speci- 

 mens they never extend clear to the posterior end. It is interesting 

 to note that in immature specimens (fig. 5) the intestinal caeca extend 

 practically to the posterior end. 



All the reproductive organs of Margeana oaZiformensis (fig. 1) 

 except the coils of the uterus which extend to the posterior end are in 

 the anterior half of the bod}-. The genital pore (fig. 2, g.p.) is located 

 slightly to the right of the mid-ventral line of the body close in front 

 of the ventral sucker. The cirrus sac (fig. 1, dr., and fig. 2) is large 

 and has strong musculature. It is located to the right side and in 

 front of the ventral sucker. It has a width about equal to the diameter 

 of the ventral sucker and a length of about three times this diameter. 



The size and proportions of the cirrus sac are shown in figure 2. 

 The posterior half of the cirrus sac contains a large seminal vesicle 

 (fig. 2, s.v.) full of sperms, which is constricted near its anterior end. 

 This is followed by a short prostate region (pr.) into which empty 

 large numbers of small unicellular prostate glands (p.g.), which fill the 

 space between the seminal vesicle and the walls of the cirrus sac, but 

 which do not extend further forward in the cirrus sac than the anterior 

 limit of the prostate region of the male duct. These glands are densely 



