TREMATODE PARASITES OF BIRDS LINTON 



9 



tangential sections the seminal vesicle is 0.5G mm, in length and 

 0.20 in diameter. Testes near the posterior end of the body, one 

 following the other, in most cases elliptical in outline and much 

 longer than broad ; ovary subglobular, nearly on the median line, or 

 a little to the right, a short distance in front of the first testis, from 

 which it is separated by the rather conspicuous shell-gland and 

 vitelline reservoir, and beginning of the uterus. Laurer's canal was 

 traced from its opening on the dorsal surface, at the level of the 

 ovary, to the vicinity of the beginning of the uterus, which appeared 

 to contain sperm and germ cells associated with ova while still 

 enveloped by the shell-gland. The vitellaria begin a little in front 

 of the base of the seminal vesicle and extend along the lateral 

 margins to the level of the posterior end of the second testis. Back 

 of this point the vitellaria in most cases fill the body. In trans- 

 verse sections the excretory vessel is seen to divide at the second 

 testis into a right and left branch, which could be traced forward 

 to the ovary, but are difficult to distinguish in sections through the 

 uterus, where, with the exception of a small area at each side 

 occupied by the vitellaria, the interior is filled with ova. The uterus 

 fills the central region of the body from the ovary to near the 

 seminal vesicle. Thence forward it is a straight duct, the metra- 

 term, which passes on the dorsal side of the vential sucker and opens 

 at the genital pore immediately in front of the cirrus. The ova 

 measure from 0.08 to 0.11 mm. in the longer, and from 0.05 to 0.06 

 in the shorter diameter. 



Following are tabulated measurements of balsam mounts from 

 different hosts. 



Length 



Maximum breadth 



Diameter of head 



Diameter of oral sucker. 



Length of pharynx 



Breadth of pharynx 



Diameter of ventral 



sucker 



Length of first testis 



Breadth of first testis... 

 Length of second testis. 

 Breadth of second testis. 



Diameter of ovarj' 



Distance of ventral 



sucker from anterior 



end 



Distance of second testis 



from posterior end 



Ovum, longer diameter- 

 Ovum, shorter diameter. 



Larus argentatus 



10.00 

 .42 

 .30 

 .08 

 .09 

 .05 



.28 

 .72 

 .25 

 .80 

 .25 

 . 15 



30 



63 



105 



06 



3.64 

 .63 

 .32 

 . 11 

 .09 

 .06 



.28 

 .25 

 .25 

 .24 

 .28 

 .17 



.45 



.31 

 .09 

 .05 



6.58 

 . 63 

 .39 

 . 11 

 . 11 

 .07 



.35 

 .42 

 .35 

 .49 

 .35 

 .20 



73 



59 

 10 

 05 



Lariis 



delawar 



ensis 



5.46 

 .35 

 .20 

 . 11 

 . 11 

 .08 



.27 

 .42 

 .20 

 .39 

 .20 

 . 13 



. 56 



.28 

 . 11 

 .06 



Larus mar- 

 inus 



7.00 

 .63 

 .27 

 .09 



28 

 65 

 35 

 70 

 20 

 18 



30 



56 



105 



063 



Larus ! Nycti- 



philadel-J corax nyc- 



phia ticorax 



8.00 



.84 

 .28 

 . 10 

 . 15 

 . 10 



.35 



42 



. 10 

 .54 



6.50 

 .50 

 . 28 

 .09 

 .08 

 .06 



.28 

 .29 

 .21 

 .39 

 .23 

 . 13 



64 



77 



096 



051 



