NO. 2071. 



NEW GENUS OF DISGODRILID WORMS— HALL. 



191 



CERATODRILUS, new genus, 1914. 



Generic diagnosis — Branchiobdellidae. — Prostomium bilobed, not 

 sharply so, each lobe fringed with 4 or 5 papillae on lips. Dental 

 plates brown, of a roughly crescentic outline, slightly dissimilar, the 

 ventral with 6 teeth, the dorsal with 7, the teeth being of compara- 

 tively uniform size (fig. 1). The antero-dorsal border of the head is 

 furnished with a membranous border deeply incised to form 4 tenta- 

 culiform appendages (figs. 2 and 3). The first 7 trunk segments are 

 furnished with dorsal appendages extending from the lateral border 

 in a pointed band, the number of points usu- 

 ally 6, but on some segments 7 or 8. Sperma- 

 theca cylindrical to flask shaped, not bifid. 

 Penis eversible. Testes in segments 5 and 6. 



Type-species.— Ceratodrilus thysanosomus, 

 new species. 



CERATODRILUS THYSANOSOMUS, new species, 1914. 



Specific diagnosis — Ceratodrilus. — Length, 2 

 to 2.8 mm. Maximum head diameter, 400 p.\ 

 maximum body diameter, 660 it; maximum 

 sucker diameter, 360 it. Maximum length of 

 cirriform appendages of head, about 180 it. 



The material sent in by Mr. Haley was in a 

 poor state of preservation, as was a second 

 consignment which he very kindly furnished. 

 I have, therefore, only undertaken a study of 

 the worm sufficient to fix it generically and specifically. An exam- 

 ination of the anterior pair of nephridia shows that the more anterior 

 nephridium extends through the first and second segments, and that 

 the posterior nephridium extends through the second, third, and 

 fourth segments, but I am unable to say from the material in my 

 possession whether these nephridia have a common opening or sepa- 

 rate openings. The rest of the [anatomy seems to conform to the 

 general type. 



Host.— "Crayfish."" 



Location. — -The collector, Mr. Haley, writes: "They were particu- 

 larly abundant among the egg masses of the female and those infested 

 seemed to weaken and die." 



Locality. — Streams of Great Basin, Salt Lake City, Utah. 



Type-specimens. — Cat. No. 17708 U.S.N.M. (Bureau of Animal 

 Industry Helminthological Collection). 



The American species of Branchiobdellidae have been reported 

 from the following localities and hosts : 



zaomm. 



Fig. 1.— Ceratodrilus thy" 

 sanosomus. Dental plates. 

 a, Ventral plate; b, Dor- 



SAL PLATE. 



