Mr. IL J. Carter on the Organization of Infusoria. 247 



culse and the papillae respectively through which their contents 

 appear to be discharged ; {b, b) radiating lines or vessels consisting 

 of a concatenation of pyriform and fusiform sinuses. This state 

 can be only partially seen, viz. when the vesiculae are just re- 

 ceiving the contents of the sinuses ; at this moment both may be 

 observed to be slightly dilated together, but never to the extent 

 represented in the diagram. 



Fig. 67. Paramecium aurelia, Ehr. ; sketch of, under compression, just 

 preceding diffluence and death; showing the dilatation of the 

 proximal sinuses only, and the passage of the rest into each 

 other, so as to form continuous vascular channels. 



Fig. 68. Ditto, not compressed ; showing a lateral view of the vesiculae in 

 situ : (a, a) dilatation of the vesiculae pressing inwards the prox- 

 imal sinuses, which are thus shown to open into the inner part of 

 the vesiculae ; {b) discharge of digestive globule through the anal 

 aperture ; (c) granules. 



Fig. 69. Ditto, in transverse fissiparation, to show the quadrupling of the 

 vesiculae. 



Fig. 70. Filament of Physactis saccata. Kg., with terminal spherical cell 

 previous to the formation of the sporangium : (a) homogeneous 

 contents of spherical cell ; (6) nucleus of ditto. 



Fig. 71. Ditto, after the formation of the sporangium: (a) spherical cell 

 now empty and connected with the sporangium by a tubular pro- 

 longation. 



Fig. 72. Spherical cell of P. saccata separated from the filament. 



Fig. 73. Ditto, with a granular development extending from the nucleus. 



Plate VII. 



Fig. 74. Epistylis Galea (?), Ehr., showing (a) entrance of buccal cavity ; 

 (h, b, b) buccal cavity with constriction armed with cilia (?) ; 

 (c, c) digestive globules in process of formation ; {d, d) ditto 

 formed and containing food ; (<?, e) small green zoospores taken 

 in as food, and showing by their circulating throughout every part 

 of the body that they are not confined to an intestinal canal; 

 (/,/) vesicula opening into the buccal cavity just above the con- 

 striction; (h) arrow marking the position of the anal aperture; 

 {g) cylindrical form of nucleus wrapped round the vesicula and 

 buccal cavity like the ovary in Salpa ; (i) closed individual. 



Fig. 75. Vorticella ?, presenting a pouch -like extension of the buccal 



cavity in the position of the anal aperture and discharging orifice 

 of the vesicula : (a) pouch ; (6) vesicula ; (c) another individual 

 passing into the Acineta form. 



Fig. 7^' V. microstoma, showing the separation of the different organs 

 under decomposition: (a) vesicula; (6) buccal cavity; (c) nu- 

 cleus ; (d) diffluent operculum. 



Fig. 77' V. convallaria (?), Ehr., to show (a) granules, (b) nucleus. 



Fig. 78. V. microstoma, to show the invisible state of the buccal cavity 

 during the dilatation of the vesicula, and vice versa: (a) with 

 vesicula ; (c) dilated ; (6) disappearance of vesicula and reap- 

 pearance of (d) buccal cavity ; (e) nucleus. 



Fig. 79. Arcellina vulgaris, Ehr., showing («, a) duality of nucleus; 

 (6, b, b) plurality of vesicula ; (c) granules ; (c?) fihform attach- 

 ments of animal to the test. Animal 1 -200th of an inch in 

 diameter. 



Fig. 80. Diffiugia tricuspis, H. J. C. (n. sp.?), showing {n) nucleus; (6) ve- 



