118 W. ARCHER. 



But it is easy to find examples in which this process is 

 complete, that is, the body of the Microgromia separated 

 into two usually anterior and posterior halves (fig. 8, a). Only 

 the former, which is produced into the pseudopodial stem 

 remains in connection with the protoplasmic network of the 

 colony. The posterior segment, which subsequently becomes 

 a zoospore, has now its connection with the mother colony 

 severed, that it is now an independent body. Both together 

 now completely fill the cavity of the test, each having its 

 nucleolated nucleus and contractile vacuole. In this condi- 

 tion the organism may persist for a long time without any per- 

 ceptible alteration. By-and-by the posterior segment becomes 

 gradually pushed up alongside the anterior one (fig. 8, b) ; 

 amoeboid movements ensuing, it slowly makes its exit from 

 the test, as it were guided along by a pseudopodium, the 

 contractile vesicle foremost, the nucleus behind. It maintains 

 for a time its amoeboid action, now becoming elongated, now 

 contracted into a globular figure, or here and there lobed 

 (fig. 8,c), which play is kept up for about a quarter of an hour ; 

 it finally assumes an ovate figure, the end containing the con- 

 tractile vacuole still in connection with the pseudopodium, 

 the end containing the nucleus outwards. About this time can 

 be noticed a tremulous movement and two flagella which seem 

 fitfully to change place, are seen waving about, but without 

 producing as yet any forward motion (fig. 8, d) . Their action 

 soon, however, becomes more regular, the zoospore unmoors 

 itself from the pseudopodium of the mother colony and swims 

 away, as an ovate body, with a constantly rotating movement. 



The anterior somewhat pointed end now consists of a some- 

 what'homogeneous plasma; it encloses the nucleus and carries 

 the two flagella ; the posterior rounded end is richly granu- 

 liferous and contains a single or double contractile vacuole. 

 Although the movement of the zoospore is not a rapid one, 

 the author was not ever able to follow it up to its coming 

 to rest ; it would always disappear amongst the unavoid- 

 able tangle of algee, &c., taken up in the drop ; he therefore 

 could not determine whether it, like the large zoospores of 

 Clathrulina elegans, passed directly by retraction of the 

 flagella into a resting state, or whether, like the zoospores 

 emanating from the cysts of that species, they passed 

 through the so-called actinophryan state. 



Certain modifications of the mode described might, how- 

 ever, take place. Thus the hinder segment on emergence 

 might assume an actinophryan aspect ; the pseudopodia 

 mostly, however, confined to the anterior end ; these might 

 sometimes anastomose, and generally resemble those of the 



