544 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 57. 



KBY XO SPECIES. 



1. Genital sucker over 100 /x i» diameter 2. 



Genital sucker less than 100 /i in diameter Cryptocotyle jejuna. 



2. Breadth of bod.v usually more than half the length; 



testes side by side; eggs 34 to 38 n long Cryptocotyle concava. 



Breadth of body usually less than half the length ; testes 

 usually obliquely one in front of other ; eggs 40 to 50 /i 

 long Cryptocotyle Imgua. 



CRYPTOCOTYLE CONCAVA (Creplin, 1825) Fischoeder. 1903. 

 Fig. 11. 



1825. Distonm concavum Cbeplin, 1825a, pp. 45-47, 83, figs. 7-8 (in Colym- 



bus rufogularis) . 

 1802. Distoma {Dicrocoelium) concavum (Creplin, 1825) Stossich, 1892c, 



pp. 158-159, 188, 189. 

 1899. Cotylogonimus {Cryptocotyle) concavum (Creplin, 1825) LtJHE, 



1899fc, p. 539 (type of Cryptocotyle). 

 1899. Tocotrema concavum (Creplin, 1825) Looss, 1899&, p. 586. 

 1903. Cryptocotyle concava (Creplin, 1825) Fischoedeb, 1903/i, p. 548. 



Specific diagnosis. — Cryptocotyle: Maximum length about 1 mm., 

 width up to 0.85 mm. Oral sucker, 60 to 87 \i in diameter. Genital 

 sucker, 150 to 300 [jl in diameter. Pharynx, about 60 \i long by 50 pi 

 broad. Esophagus about 95 \i long. Testes slightly lobed, trans- 

 ^ versely elongated, side by side, right and left; may attain 300 fx in 

 major diameter. Ovary transversely elongated, slightly lobed. 

 Eggs 34 to 38 [Jl long by 16 to 20 y. wide. 



Hosts. — Urinator stellatus^ Colyrribus cristatus, Colymbus nigri- 

 collis, Mergus merga/nser., Mergus serrata, Anas homshucMi, Nyroca 

 marila^ Nyroca clangula., Nyroca hyemalis, Oidemia fibsca, Alca 

 torda^ Colyrribus rufogularis^ Harelda gladdlis., Larus glaucus^ 

 PhalacTocorax graculus. 



Location. — Small and large intestines. 



Localities collected. — Europe. 



CRYPTOCOTYLE LINGUA (Creplin, 1825) Fischoeder, 1903. 

 Figs. 12-15. 



1825. Distomtim lingua Creplin, 1825o, pp. 47-48 (in Larus marinus v. 

 maximus; apparently Europe). 



1899. Tocotrema lingua (Creplin, 1825) Looss, 1899&, p. 586 (type of Toco- 

 trema). 



1903. Cryptocotyle lingua (Creplin, 1825) Fischoedeb, 1903?i, p. 548. 



1905. Dermocystis ctenolabri Staffokd, 1905a, p. 682 (in gills and skin of 

 Ctenolabrus adspersus). 



1918. Hallum, caninum Wigdok, 1918, pp. 254-257, figs. 1-4 (type of Hallum; 

 in dog. Detroit, Mich.). 



Specific diagnosis. — Cryptocotyle: Length, 0,55 mm. to 2 mm., or 

 slightly more than 2 mm. in extended specimens: usually (Jager- 



