the fauna of boulder county 247 



Phylum COELENTERATA 

 Class HYDROZOA 



Represented in our fauna by the freshwater genus Hydra Linne, the species not 

 determined. I have seen a specimen collected by Mr. L. C. Bragg. 



Phylum ECHINODERMATA 



These marine animals may be found fossil in our Mesozoic rocks. 



Phylum VERMIDEA 



Our district has undoubtedly a rich fauna of worms and rotifers, but they have 

 been almost wholly neglected. I therefore give only a brief account of the group, 

 enumerating the few recorded forms and indicating some which are certain or 

 likely to be found. 



Class PLATYHELMINTHIA (Flat Worms) 

 Order TURBELLARIA Ehrenberg 



Freshwater Planarians undoubtedly occur in our fauna. They are slug-like, very 

 flat, and slowly ghde oyer the stones in pools and streams. According to Gamble 

 Planaria alpina Dana is characteristic of cold mountain streams. 



Order TREMATODA 



Includes the parasitic liver-fluke and related forms. The larva of the liver-fluke 

 lives in small snails of the genus Lymnma. Professor H. S. Pratt has published a 

 synopsis of North American Trematoda in American Naturalist (1902). Many 

 of the species have hosts which occur in Boidder County. 



Order CESTODA 



The tape-worm, of which we doubtless have several species. Many of the recorded 

 hosts occur with us. For Cestoda of cattle, sheep, etc., see Stiles and Has- 

 sall. Bull. No. 4, Bureau of Animal Industry, U.S. Dept. Agriculture (1893); 

 of dogs, see M. C. Hall. Proc. U.S. Nat. Museum (1910); of rabbits, see M. C. 

 Hall, Proc. U.S. Nat. Museum (1908); of birds, see B. H. Ransom, Bull No. 6g, 

 U.S. Natl. Museum (1909); of fishes, see Linton, Proc. U.S. Nat. Museum (1897). 



Class NEMATHELMINTHIA 

 Order NEMATODA (Thread-Worms) 



Our fauna undoubtedly includes many thread-worms, both parasitic and free- 

 living. The latter have often been seen in water, but halve not been studied. 



Family FILARIID^ 

 (87) Fiiaria Miiller. An immature worm, apparently of this genus, was found 

 by Terry Duce and Willard Rusk in the neck of an owl, Asio wilsonianus, ob 



