370 SPOROZOA. 



Doubtful Protozoa. 



Genus RHINOSPORIDIUM Minchin & Fantham, 1905. 



Rhinosporidium, Minchin & Fantham, 1905, pp. 521-32 ; Minchin, 

 1912, pp. 424-5 ; Castellani & Chalmers, 1919, pp. 533-4 ; 

 Ashworth, 1923, pp. 301-42 ; Hegner & Taliaferro, 1924, pp. 375- 

 7 ; Wenyon, 1926, pp. 776-8 ; Knowles, 1928, pp. 338-42 ; 

 Reichenow, 1929, pp. 1136-7. 



Organisms giving rise to polypi, especially in the nose, of 

 human beings and horses. Believed for a long time to belong 

 to Haplosporidia, but now generally recognized as a fungus. 



304. Rhinosporidium seeberi (Wernicke). (Fig. 182.) 



Coccidium seeberi, Wernicke, 1900. 



?, O'Kinealy, 1903 a, pp. 109-12 ; 1903 b, pp. 43-4, 1 pi. 

 ■\Rhinosporidiuni kinealyi, Minchin. & Fantham, 1905, pp. 521-32, 



pis. XXX, xxxi. 

 Rhinosporidium seeberi, Minchin, 1912, pp. 424—5. 

 ■f Rhinosporidium kinealyi, Tirumurti, 1914, pp. 703-19. 

 ■f Rhinosporidium seeberi, Castellani & Chalmers, 1919, pp. 533-4, 



fig. 190 ; Ashworth, 1923, pp. 301-42, 5 pis. 

 Rhinosporidium seeberi, Hegner & Taliaferro, 1924, pp. 375—7, 

 fig. 141 ; Wenyon, 1926, pp. 777-8, figs. 335, 336 ; Reichenow, 

 1929, pp. 1136-7, fig. 1141. 



The youngest forms are spherical bodies, about 6 ju in diameter, 

 embedded in the cytoplasm of connective tissue cells, with 

 chitinoid envelope, vacuolated cytoplasm, and a vesicular 

 nucleus containing a karyosome. Growth is accompanied 

 by nuclear multiphcation and the cytoplasm becomes laden 

 with numerous food-granules. When the parasite is about 

 100/x in diameter and has about 128 nuclei the chitinous en- 

 velope becomes much thickened by the deposition of cellulose 

 on the inner surface, except at one point where the future 

 pore will be formed. Nuclear divisions contitiue, and when 

 there are about 4,000 nuclei the cytoplasm divides into rounded 

 cells, which divide twice to form about 16,000 young spores 

 within the sporangium. In the mature sporangium there are 

 usually fully developed spores in the centre, and small, immature 

 ones arranged peripherally. The fully-formed spore has a 

 chitinous envelope, a vesicular nucleus with a karyosome, 

 and cytoplasm containing one to sixteen refringent spherules 

 of reserve food material. The spores are spherical or oval. 

 They are discharged in hundreds through the pore of the 

 sporangium, and are scattered throughout the connective 

 tissue by the lymph exudate. The reserve food material is 

 gradually used up and the spores enter into fresh connective 

 tissue cells to repeat the cycle. The ripe sporangia are seen 

 as white dots covering the surface of the nasal polypus. 



