144 PROCEEDINGS OF THE NATIONAL. MUSEUM vol.88 



Record of collections. — From dollarfish: Three, collected July 24, 

 1918. Two (U.S.N.M. No. 8374), collected July 25, 1918. 



From chub mackerel: One, collected August 15, 1918, fragment, 

 suckers missing. Excretory vessel, dark brown, slender, extends 

 from posterior end to anterior edge of testes, where it divides into 

 two lateral vessels; length, 5 mm. 



Twelve, collected August 19, 1918. Some of these are fragments 

 as on previous date. The suckers adhere to the mucous membrane 

 of the host and the worms have a tendency to break behind the ven- 

 tral sucker unless care is taken in removing them. Measurements, 

 life: Length, 6 mm.; oral sucker, length, 0.48 mm., breadth, 0.38 

 mm.; pharynx, length, 0.42 mm., breadth, 0.20 mm.; diameter of 

 ventral sucker, 0.42 mm. Length very variable, depending on the 

 degree of contraction. 



Fifteen and several fragments, collected August 31, ; very 



extensible, some of them stretching to a length of 15 mm. or more. 



Collection of August 22, 1910. Number not noted. Color of body 

 reddish, neck translucent-white, entire. Length as much as 6 mm. 

 Measurements, life: Length, 5.36 mm.; breadth, 0.87 mm.; oral 

 sucker, length, 0.58 mm. ; breadth, anterior, 0.56 mm., posterior, 0.21 

 mm.; pharynx, length 0.56 mm., breadth, anterior, 0.21 mm., pos- 

 terior, 0.25 mm. ; ventral sucker, length, 0.49 mm., breadth, 0.54 mm. ; 

 ova, 0.02 by 0.01 mm. 



Seventeen, collected August 18, 1920; various contraction forms, 

 with tendenc}^ to be somewhat swollen toward the posterior end when 

 the appendix is retracted. Seven (U.S.N.M. No. 8375), collected 

 July 21, 1928; actively contracting and extending, from 4 to 9 mm. 



Five, collected August 6, 1928; 3 to 7 mm., translucent, reddish 

 yellow in region of uterus. One (U.S.N.M. No. 8376), collected 

 Aug-ust 23, 1928. Six, collected July 6, 1929; 3 fishes examined. 

 Thirty-two, collected 3u\y 11, 1929; 3 fishes examined. Four, col- 

 lected July 29, 1929; 3 fishes examined. Twenty-eight, collected 

 August 19, 1929; 3 fishes examined. 



From common mackerel: Two (U.S.N.M. No. 8377), collected 

 August 10, 1906. Measurements, life : Length, 7 mm. ; diameter, an- 

 terior, 0.37 mm., middle, 0.84 mm., thence tapering to 0.28 mm. or 

 less at the posterior end; oral svicker, length, 0.49 mm., breadth, 

 0.28 mm. ; pharynx, length, 0.42 mm., breadth, 0.16 mm. ; diameter of 

 ventral sucker, 0.35 mm. ; ova, 0.02 by 0.01 mm. 



CYST CONTAINING TREMATODE OVA 



Plate 11, Figtjeb 108 



A cyst from the wall of the postbranchial chamber of a summer 

 flounder iParalichthys dentatus)^ collected by Dr. C. W. Hahn, July 



