42 BRITISH FRESHWATER KHIZOPODA. 



out its destruction the protoplasmic body cannot be 

 examined. It was on this species that Verworn (1888) 

 experimented in order to determine whether a difflugiari 

 rhizopod had the power of reconstructing or repairing 

 its damaged test. He found that regeneration of the 

 injured or completely-removed test, by the proto- 

 plasmic body, does not occur, although the vital func- 

 tions take their course in normal fashion.* The same 

 observer demonstrated that the structure of the test is 

 completed, when fission takes place, at the moment of 

 separation of the new individual. No subsequent 

 alterations occur and no after-growth takes place. 



FIG. 57. Dijflugia urceolata with plain crown. Bowness, Westmore- 

 land. From a drawing by G. S. West, x 310. 



These conclusions corroborate Gruber's, on the same 

 point, arrived at from independent observations. 



The species seems quite indifferent to climate or 

 altitude. In America Leidy found it flourishing 

 abundantly in swampy pools in New Jersey and 

 equally so at an elevation of 10,000 feet in Wyoming- 

 Territory. Examples varied in the crown being plain, 

 or furnished with spines conical, acuminate, or acute. 

 The spined form apparently identical with our 

 own occurred in sphagnous pools, together with a 

 variety (var. olla) distinguished by the peculiarity 

 of having its spines mostly blunt and tipped with a 



* ' Zeitschr. fiir wiss. Zool./ Bd. xlvi, pp. 455-461. 



