236 



BUIJ.ETIX 120, UNITED STATES NATIONAL MUSEUM. 



than in O. mriarum. The species seems to be distinct, but to resemble 

 0. japonica. This resemblance between an eastern Asiatic form and 

 a western American form will be noted in our discussion of geo- 

 graphical distribution as probably indicating a late migration 

 from Siberia to Alaska and south between the mountains and the 

 Pacific ocean. Opalina draytonil seems clearly to belong in the 

 group O palinae latac. Avhich is an Eastern Hemisphere group. 



a 



Fig. 210. -Oi'alin'a draytonii : o and b, groups of animals from two dikfbkbnt 



l.VrECTIONS, X 117 niAMETERS. IN INFECTION & WERE NUMEROUS ANIMALS IN FISSION 

 AND THE PRESENCB OF NUMEROUS SMALL CELLS WAS PROBABLY DUE TO THE PREVALEffCD 

 OP DIVISION IH THIS INFKCTION. 



OPALINA PANAMENSIS, new species. 



7'?//;e.— United States National Museum Cat. No. 16606. 



Host. — Biifo typhoniiis (Linnaeus), two infections, from Bahia 

 Solada, Panama; J. F. Bransford, collector. The type infection is 

 from United States National Museum specimen No. 25176, 32 mm. 

 long. 



Measurements of a good-sized individual. — Length of body 0.177 

 mm.; width of body 0.115 mm.; thickness of body, anterior 0.015 

 mm., middle 0.015 mm., posterior 0.018 mm.; diameter of nucleus 

 0.0048 mm. to 0.0056 mm., mean 0.0055 mm.; cilia line interval, an- 

 terior 0.00105, posterior 0.0032 mm. 



