16 



PROCEEDINGS OF THE NATIONAL MUSEUM 



testis somewhat triangular in outline, breadth 

 0.49, length 0.35. In lateral view the testes 

 are somewhat quadrilateral in outline. (Cat. 

 No. 7929, U.S.N.M.) 



Larus Philadelphia, 



1912, November 15. 



December 21. 



(Cat. No. 



1. Length in balsam 4.62. 

 5. From 3 to 4 mm. in length. 

 7930, U.S.N.M.) 



1914, November 13. 8. Slender, longest about 4 mm. 



Golyvibus auritus. 



1905, December 25. 2. Length in formalin 4.5 mm. 



Golymbus holbolli. 



1914, February 18. 2. Lengths approximately 2.5 and 4 mm. In 



each the diameter of the oral sucker is 0.14, 

 of the ventral sucker 0.28; ovum 0.08 by 

 0.05; length of oral spines 0.07. One of the 

 worms is slender, length 4 mm.; maximum 

 breadth, at level of testes 0.38; first testis, 

 length 0.28, breadth 0.24 ; second testis, length 

 0.35, breadth 0.24. The other is fusiform 

 (fig. 41), length 2.5 mm.; maximum diam- 

 eter 0.64; first testis, lengih 0.14, breadth 

 0.42 ; second testis, length 0.24, breadth 0.29. 

 (Cat. No. 7931, U.S.N.M.) 



These distomes, while differing considerably in 

 the proportions of the body behind the testes, 

 agree in all essentials with those from the 

 herring gull. Lengths, in balsam, from 1.50 

 to 3.15 mm., breadths from 0.21 to 0.38. 

 The ratio of the portion of the body behind 

 the testes to that in front of the testes varies 

 from 1 :1 to 2 :1. The vitellaria extend to the 

 anterior edge of the first testis in one, to the 

 posterior edge of the first testis in another, 

 and to about the middle of the first testis in 

 the others : ova 0.09 by 0.054. (Cat. No. 7932, 

 U.S.N.M.) 



This specimen differs from tliose of the fore- 

 going date in the relatively short post-testic- 

 ular region. (Fig. 42.) Dimensions in bal- 

 sam: Length 2.20; breadth 0.70; diameter of 

 oral sucker 0.13, of pharynx 0.08, of ventral 

 sucker 0.30; length of pharynx 0.10, of ven- 



Gavia immer. 

 1911, July 24. 



5. 



September 1. 1 



