236 
Argas persims 
into longitudinal and transverse bands. Many of the fibres anasto¬ 
mose, and in those cases where the ends are free, the termination 
of the fibre is split up, fan-wise, into a number of fibrils which lose 
themselves in the basement membrane supporting the epithelial layer. 
The muscle bands, and particularly the terminal fibidls, show a regular 
transverse beading, the only evidence of their transversely striated 
nature, but this feature is not always visible, its successful demonstration 
being largely dependent upon the method of fixation and staining used. 
Fig. 3 (PI. XVII) was drawn from a portion of the wall of one of the 
alimentary coeca removed in the fresh state, opened out and spread on 
a glass slip, fixed with Carnoy’s Fluid and stained with Ehrlich’s so- 
called “tri-acid” mixture (Orange G., Saurefuchsin and Methyl Green). 
The nuclei which appear in the preparation are those of the epithelial 
cells which still remained attached to the basement membrane, the 
majority having been intentionally removed by gently dabbing the 
epithelial surface with a fine soft brush prior to staining. 
In the living tick, peristaltic contractions of the alimentary coeca 
may be observed through the translucent integument, the movements 
being particularly active immediately after engorgement. 
The Rectum. 
Plates XIV and XV, t. c. 
We have applied the term “rectum'’ to the narrow, comparatively 
short tube which establishes communication between the stomach and 
the rectal sac, but, as both the rectum and rectal sac of the Ixodoidea 
are derived from the mesenteron, the terminology is not strictly correct. 
In the literature on the subject, this portion of the alimentary canal 
of the tick has received many names. Heller^ called it the intestine 
(Darm): Nordenskiold- refers to it as the pylorus: Bonnet® and others 
deny its existence altogether, the former describing the stomach with 
its appendages as un organs aveugle sans communication avec le “'rectum” 
ou vesicule excretice. Blanc*, in a paper dealing solely with this subject, 
terras it the hibe communicatif and applies the term rectum to the 
rectal sac. For fuller information the reader is referred to his paper, 
which contains a very complete account of the comparative anatomy of 
this portion of the alimentary canal in the Ixodoidea. 
* Heller, C. (1858), p. 307. 
3 Bonnet, A. (1907), pp. 61-66, 83. 
- Nordenskiold, E. (1908), p. 646. 
•* Blanc, G. (1910). 
