TREMATODE PARASITES OF BIRDS LINTON 



15 



1927, August 13 

 Larus atricilla. 

 1904, August 12 



0.56 ; diameter of oral sucker 0.10, of pharynx 

 0.06, of ventral sucker 0.24; length of 

 pharynx 0.10; ovum 0.08 by 0.05; length of 

 oral spines about 0.07, breadth about 0.02. 



gulls examined, 2 distomes from one, 1 from 

 the other; ova 0.080 by 0.068. 

 1911, July 24. 2. Dimensions, balsam: Length 3.32; maxi- 



mum breadth 0.46 ; diameter of head 0.22, of 

 oral sucker 0.11, of pharynx 0.07, of ventral 

 sucker 0.25; length of pharynx 0.09; ovary, 

 length 0.16, breadth 0.21 ; first testis, length 

 0.29, breadth 0.31; second testis, length 0.59, 

 breadth 0.38. (Cat. No. 7927, U.S.N.M.) 



Larus delawarensis. 

 1914, January 24. 



Larus marinus. 

 1914, April 28. 



9. Note on formalin material : Slender, flaccid, 

 and slightly macerated; most of the oral 

 spines and all of the body spines missing. 

 Dimensions in balsalm: Length 6.45; maxi- 

 mum breadth 0.39; diameter of oral sucker 

 0.09, of pharynx 0.06, of ventral sucker 0.27 ; 

 length of pharynx 0.09; diameter of ovary 

 0.14; first testis, length 0.36, breadth 0.25; 

 second testis, length 0.67, breadth 0.24; ovum 

 0.087 by 0.051. (Cat. No. 7928, U.S.N.M.) 



Length, in balsam, 4 mm. As nearly as can 

 be made out there are 22 spines around the 

 mouth, 0.069 in length and 0.018 in breadth. 

 The neck is thickly beset with stout spines 

 arranged in diagonal rows. There is a space 

 on the neck of about 0.15 between the oral 

 spines and the neck spines which is smooth. 

 The spines become sparse toward the base 

 of the neck, but may be seen along the mar- 

 gin of the body back to a point opposite the 

 middle of the posterior testis. The testes are 

 situated at about the middle of the length of 

 the body, contiguous with each other in one, 

 separated by a short space in the other. In 

 ventral view the anterior testis is elliptical in 

 outline, but with its anterior border nearly 

 straight, breadth 0.49, length 0.25; posterior 



