8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



In some cases the protoplasm immediately surrounding these nuclei 

 has a yellowish red color, as though, perhaps, it contained material 

 which was passing in towards the nucleus. The nuclei lo ft in di- 

 ameter are found in the later stages now described. They acquire 

 stronger staining powers as the sphere stage is approached. 



Continued July 21. — The duration of the stage in which the pro- 

 toplasm remains in the condition of closely aggregated spheres, and 

 which I call stage iii, varies from two to eight hours. The aver- 

 age duration in a number of cases is about four hours. The most 

 marked change which can be seen in the living condition during this 

 period is in the disposition of the brown granules in the spheres. 

 At first the center of the spheres is clear, the granules lying at their 

 periphery, while in the later part of the stage the granules occupy 

 the sphere leaving only a clear layer at the periphery. 



After stage iii the development may pursue one of two courses : 



I. In by far the greater number of cases that I have watched the 

 spheres lose their sharply defined outline and gradually fuse with 

 one another into one or a few lumps.^ Sometimes long pseudopodia 

 are thrown out during the process of fusion but this does not always 

 occur. The lumps so found generally divide, forming smaller lumps 

 of varying size which move apart by means of pseudopodia, and also 

 exhibit amoeboid changes of form. It frequently occurs that one of 

 these lumps attaches itself to the empty shell, spreading over part 

 of the exterior and interior." 



The protoplasm remains in this condition for weeks. The smaller 

 lumps appear gradually to break up into granules, losing their definite 

 outline and apparently dying. The large lumps may retain their sharply 

 defined outline for weeks, the movement of the protoplasm becoming 

 gradually more sluggish, and the volume of the mass apparently de- 

 creasing. What their ultimate fate may be I have not seen — but it 

 appears probable that it is the same as that of the smaller divisions 

 (lumps) into which the protoplasm divided — gradually disintegrating.^ 



' 7 : 30-9 : 30 p. m. 



^ II : 30 p. m. 



^ These conditions lasted until July i, many other specimens being kept under 

 observation. On this date Lister tabulates the stages of the process as follows : 

 Stage I. Premonitory halo formed but protoplasm still in shell. Stage 2. Proto- 

 plasm emerged from shell but still in one mass. Stage 3. Protoplasm divided 

 up into isolated spheres. Stage 4. Spheres fused to form a common mass 

 sending out pseudopodia. Stage 5. The mass divided up into amoeboid lumps 

 with pseudopodia. Lister's preparations of shells in all of these stages are in our 

 collection at South Kensington. 



