180 ANIMALS AND PLANTS vi 



form of monad which he has named Heteromita. 

 I shall, therefore, call it not Monas, but Hcteromita 

 lens. 



I have been unable to devote to my Heteromita 

 the prolonged study needful to work out its whole 

 history, which Avould involve weeks, or it may be 

 months, of unremitting attention. But I the less 

 regret this circumstance, as some remarkable 

 observations recently published by Messrs. Dai- 

 linger and Drysdale l on certain Monads, relate, 

 in part, to a form so similar to my Heteromita 

 lens, that the history of the one may be used to 

 illustrate that of the other. These most patient 

 and painstaking observers, who employed the 

 highest attainable powers of the microscope and, 

 relieving one another, kept watch day and night 

 over the same individual monads, have been 

 enabled to trace out the whole history of their 

 Heteromita ; which they found in infusions of the 

 heads of fishes of the Cod tribe. 



Of the four monads described and figured by 

 these investigators, one, as I have said, very 

 closely resembles Heteromita lens in every 

 particular, except that it has a separately dis- 

 tinguishable central particle or " nucleus," which 

 is not certainly to be made out in Heteromita 

 lens ; and that nothing is said by Messrs. Dallinger 



1 " Researches in the Life-history of a Cercomonad : a Lesson 

 in Biogenesis"; and "Further Researches in the Life-history 

 of the Monads." Monthly Microscopical Journal, 1873. 



