20 PORTER. 
EXPLANATION OF PLATE III. - 
Gregarine parasitic in Rhyncobolus Americanus. 
Fic. 37. Normal appearance of a detached gregarine. X 77. 
Fic. 38. Individual with two nuclei, perhaps about to divide. X 77. 
Fic. 39. Gregarine, possibly just after division has taken place. X 77. 
Fic. 40. Longitudinal section showing -apparently a thick cuticular wall. 
X 187. 
Fic. 41. Cross section through the middle of the parasite showing the actual 
thickness of the cuticula and the longitudinal folds into which it is thrown. X 
1100. 
mu, circular muscle fibres, in this case somewhat relaxed. 
Fic. 42. Cross section, the circular muscular fibres (mz) contracted. X 
1100. 
Fic. 43. Surface view, focusing at the level of the bottom of the furrows 
(sz/), and showing the circular muscle fibres (wz). X 1100. 
Fic. 44. Section through the anterior end of the gregarine. X 1100. The 
protomerite (f7’mer) is seen to be filled with finely granular compact protoplasm. 
The conical epimerite (e’#er), terminates in a long slender filament (//), and is 
enveloped in a loose mass of protoplasmic substance (f7’f/), probably derived 
from the intestinal epithelium of the host. 
fas, thickened cuticular band forming a rim around the cup-shaped depression. 
This is left behind whenever the epimerite is torn away from the protomerite. 
Fic. 45. Section through the cup-shaped depression at the anterior end of the 
gregarine. X II0oo. 
Fic. 46. Section through anterior end of gregarine. X goo. 
cp. sng, blood corpuscles scattered in the protoplasm from host. 
Fic. 47. Surface view of anterior tip of gregarine. The most of the epimerite 
has been cut away. Tooth-like processes (de) can be seen projecting radially into 
the base of the epimerite, which remains in the cup-shaped depression. X II0o. 
Fic. 48. Side view of the cup-shaped depression and the anterior tip of the 
gregarine. X II00o. 
Fic. 49. Section through the protomerite. In the middle of the figure the 
radial ridges (crs) are cut crosswise. X I100. 
Fics. 50-52. Different forms and positions assumed by living gregarines. 
Fic. 53. Outline of the head of a living gregarine when pressed against the 
cover glass and used as a sucker. 
