Digestive Processes in Arachnids. By II. M. Bernard. 443 
We have, then, in the foregoing pages, examined some of the 
digestive processes, as revealed under the Microscope, in the Chernetidae, 
the Scorpionidae, the Araneidae, and the Galeodidae, and, very cur- 
sorily, of the Phalangiidae and the Acaridae, and found that in all 
cases the process is essentially the same. We find that the so-called 
“liver” is no true liver, but merely a tubular enlargement of the 
digestive surface. We have further found in Scorpio, traces of extra- 
enteric digestion in the mesodermal cells surrounding the alimentary 
canal, and that this process probably occurs in the Araneids also, 
where the Malpighian tubules are utilized to remove the faecal 
remains, which however are found in such quantities in the peritoneal 
cells that we are driven to the conclusion that the greater portion of 
them are derived directly from the digestive tubules. While, lastly, 
in some Acarines, chalky matter is found in the body-cavity, which 
the animals are unable to get rid of at all. This physiological 
resemblance between the Acarines and the Araneids is interesting in 
connection with the morphological evidence of their affinities.* 
The only important Arachnids which we have not examined are 
the Phrynidae and the Tely phonic! ae, which are so clearly related to the 
Scorpionidae that we are perhaps justified for the present in assuming 
that their digestive processes would not differ in essentials from what 
we have described. These animals would, however, probably repay 
examination, as nothing can be more instructive than the study of 
slight variations in details. It is only by this comparative method of 
research that we can gain any true insight into the vital processes 
of animal life. 
* ‘ Some Observations on the Relation of the Acaridae to the Arachnida,” Linn. 
Soc. Journ. Zool., xxiv. 
