244 Description of the Plates. 



Its power of executing- active movements is due to the contractility 

 of its amorphous protoplasm or cytoplasm. 



a. Anterior part of body or ' head/ The part upon which the 



line a abuts is of dark colour, to denote the presence there 

 of the opaque fatt}^ granules which g-ive the adult Grega- 

 rines their milk-white appearance. 



b. Posterior half of body, the integument or cell-wall being 



slightly removed from the contained parenchyma, as it may 

 be by imbibition of water, though in the normal condition 

 of the parts it is not very sharply limited off from it. 



c. Proboscis, into which it will be observed the granular opaque 



element of the parenchyma does not extend. 



d. Apical expansion armed with excretions of the cell-membrane 



in the form of spines. 



e. Should have pointed to the line of compartmental severance 



between the two halves of the body, and this diaphragm 

 should, according to Kolliker, have been drawn as produced 

 by the contained protoplasm, not by the enveloping cell- wall. 

 /. Nucleus containing a number of brightly refracting granules. 

 It is not known to be directly concerned with the reproduc- 

 tion of these Protozoa, as is the ' nucleus^ of Infusoria, or at 

 least not more directly than by being involved in the general 

 solution and rearrangement into small round masses, and ulti- 

 mately into ' pseudonavicellae,^ which the entire parenchyma 

 undergoes after encystation, and which constitutes most of 

 what we know of the developmental history of Gregarinae. 



See, for a general account of the Gregarinae, Kolliker, Icones His- 

 tiologicae, i., p. 7. See also Lieberkuhn, Archiv. fiir Anatomic 

 und Physiologic, 1865, p. 508 j Lankester, Quarterly Journal of 

 Microscopical Society, vol. vi., p. 23 ; Stein, Der Organismus 

 der Infusionsthiere, ii., 1867, pp. 6-8, 19, 20. 



For the possibility of a subsistence of a relationship between the 

 organisms known as ' psorospermiae ' and ' pseudentozoa ' and the 

 Gregarinae, see Leuckart, Die Mensrehlichen Parasiten, pp. 141, 

 743 ; Beale, Third Report of Cattle Plague Commissioners, 

 1866, Appendix, pp. 141-144; Cobbold, On the Nature of 

 Pseudentozoa found in Diseased and Healthy Cattle, Entozoa, 

 Supplement, 1 869, p. 40. 



