BERTRAMIA KIRKMANI. 17 



Fig. 14. — x 2000 diameters. This trophozoite was suiTOunded by a 

 thin cyst (t. cy.), and it contained ripe spores and also a considerable 

 amount of residiial trophoplasm (r.p.). The presence of residnal 

 trophoplasm is apparently quite abnormal in this organism ; and pro- 

 bably it should be regarded as a reversion to a more typical myxo- 

 sporidium ancestor. 



Fig. 15. — X 2000. A cyst which has bui'st and liberated the spores 

 l)y its elasticity. 



Fig. 16. — x 4000 diameters. Youngest spore, drawn from a specimen 

 in the same condition as Fig. 9. The nucleus (h.), which is the same as 

 the nuclei in Fig 8, «., has no nucleai" membrane, and the chromatin 

 lies around the pei'ii^hery. 



Fig. 17. — X 2000 diameters. (1) Nucleus in youngest trophozoite 

 (Fig. 1). (2) Nucleus preparing to divide, nuclear memln-ane dis- 

 appearing (Fig. 4). (3) Nucleus preparing to divide. (4) Nucleus pre- 

 paring to divide, the chromatin around the pei'iphery dividing into two 

 plates (Fig. 4). (5) Chromatin plates separated and connected together 

 by achi-omatic spindle (Fig. 2). (6) One of the daughter nuclei (Fig. 2, 

 d.7i.}. (7) Daughter nucleus passing into the resting condition. (8) 

 Formation of niiclear membrane (Fig. 6). (9) Resting nucleus of adult 

 trophozoite; it is about half the size of (1) (Fig. 7). Preparatory to 

 the formation of spores the karyosome swells up until it reaches about 

 the diameter of the whole nucleus (7). The nuclear membrane is not 

 distinct (Fig. 8). 



Fig. 18. — x 4000 diameters. (1-4) Stages in the formation of the 

 6-10 nuclei of the ripe spore ; the chromatin first appearing in the form 

 of a band. (5-8) Stages in the foi-mation of the 6-10 nuclei of the ripe 

 spore ; the chromatin first appearing in the form of a ring or hoop. 



Fig. 19. — x 8000 diameters. Ripe spore showing operculum (?.), ten 

 nuclei (n.). so-called " vacuole" ((,'.), and problematical granule (g.). 



Explanation of Reference Letters. 



c. a. Clear area around nucleus, cij. Thick-walled cyst. ch.b. Chro- 

 matic body of spore. d. Dyaster stage in dividing nucleus, d. n. 

 Daughter nuclei after division, d.n.m. Disappearing nuclear mem- 

 brane, ec. Ectoplasm. en. Endojilasm. y. Granule imbedded in 

 vacuole of spore, gr. Granules in eudoplasm. k. Karyosome. /. Lid 

 or operculum of spore membrane. /. gr. Large granule surrounded hj 

 clear area. »i. Nucleus. «.(?. Nuclei preparing for karyokinesis. n.m. 

 Nuclear membrane, n.m.f. Nuclear membrane forming, r.p. Residual 

 trophoplasm. s. gr. Small granules. sp. Spore. sp. w. Spore-wall. 

 t. Trabecula. t-cy. Thin-walled cyst. t.f. Trabeculse forming, itn.p. 

 Undivided trophoplasm. v. So-called vacuole of spore. t\. Vacuole of 

 trophoplasm. 



VOL. 1, PART J. 2 



