338 GENEEAL HISTORY OF THE INFUSORIA. 



The notice of Mr. Carter, of the peculiar structures he would designate 

 spermatozoids, is as yet unconfirmed by other writers ; and we must therefore 

 consider their natiu'e and purpose still suh jiidice. 



Since the above was wi'itten, M. Balbiani's researches (A. N. H. 1858, vol. i. 

 p. 435) confirm Mr. Carter's opinion so far as relates to the development of 

 spermatozoids or male reproductive elements, but refers their origin to the nu- 

 cleolus instead of the nucleus. In our history of these last-named organs, we 

 have presented M. Balbiani's vieAvs, and must here refer back to them (p. 329). 



Accessory Contents : — Granules ; Molecules ; Spherical Cells ; Sup- 

 posed Glands. — Among the remaining contents of the Ciliata are numerous 

 granules, molecules and fat-cells. Mr. Carter {A. N. H. 1856, xviii. p. 121) 

 makes a distinction between granules and molecules — two terms which by 

 others are very loosely used and not specially defined. This writer, however, 

 would restrict the term molecules (moleculae) to colouiiess granules more 

 minute than those he understands by the latter appellation. " They differ in 

 size, and are the first bodies that appear in it (/. e. the sarcode). ... By the 

 time the ovules have become fully formed, the sarcode and its moleculge have 

 died off or disappeared." 



The granules " make their appearance among the molecultc, and are cir- 

 culated round the abdominal cavity in the manner of the digestive globules 

 and particles of food. They are of different sizes, but chiefly characterized 

 by being much larger than the moleculae, few in number, of a circular, ellip- 

 tical, elongated, subround, or irregular shape, Tvith thick dark edges, appa- 

 rently produced by obstmction to the passage of light, — coloiuless, or of a 

 yellowish-green tint. When large, and Avith no other granular matters pre- 

 sent but the moleculae, they form a striking feature in the interior of Amoeba, 

 VorticeUa, Oxytricha, Paramecium AureJia, &c. ; but at times they are so in- 

 significant in size as to be undistinguishable from the moleculae, even if 

 present at all. That they are not ovules may be satisfactorily seen when 

 both are together, — the dark, thick, and frequently irregular edges and colour- 

 less state of the former contrasting strongly with the thin circular margin 

 and faint yellow tint of the latter. They appear to increase in size and 

 number vrith the age of the Infusorium, and, when fully developed, to remain 

 unaltered in size, though apparently somewhat shrivelled in form, until their 

 dissolution. On one occasion, while watching the metamorphosis of an Oxy- 

 triclia (similar to, but not the same as, that described by M. Jules Haime, 

 and of which I hope to give a detailed accoimt hereafter), these granules, 

 during the formation of the globular cell within the body, which enclosed the 

 materials from which the Ploesconia was ultimately developed, became con- 

 gregated together at the posterior extremity of the Occytricha, and remained 

 there in a roundish mass, shut out from the cell, until the latter burst for 

 the liberation of the Ploesconia, when, with the deciduous coverings, they 

 passed into dissolution. Of the nature of their ofiice I am ignorant ; but they 

 are sufficiently remarkable and constant to demand particular notice." 



Perty speaks of molecules and granules together, and expresses his opinion 

 that some are simple fat-corpuscles, and others the first rudiments of internal 

 germs or ovules. Stein also carefully distinguishes fat-granules from others 

 not fatty. In Opercularia, Epistylis, and alhed genera of Vorticellina , this 

 observer points out that no particles of food penetrate to the posterior extre- 

 mity, where its diameter is narrowed to unite with the stem, but that this 

 region is occupied with a heap of large fat-corpuscles and of minute granules 

 of probably the same nature. Isolated corpuscles resemble precisely the fat- 

 particles scattered through the body. He cannot assent to Ehrenberg's pro- 

 position, that this heap of granules represents a sort of loose ovary, but would 



