44 SPECIAL ANATOMY OF THE TERRESTRIAL 



quentlj contains numbers of an entozoon, which I have 

 named Distoma vagans} The blood-vessels, especially 

 in the liver, exhibit a white, opaque appearance, which 

 is dependent upon the deposit in the sides of the vessel 

 of innumerable, oil-like granules. 



The blood contains numerous blood-corpuscles, which 

 vary in size, are granular, and exhibit numerous radiat- 

 ing, projecting points of variable length, — frequently 

 greater than the diameter of the corpuscle. 



The pulmonary cavity is lined with a tessellated epi- 

 thelium, the cells of which are faintly granular, with a 

 few coarser granules, and a distinct, round or oval, gra- 

 nular, nucleolated nucleus. 



The renal organ is a gland which exhibits a foliated, 

 or plicated appearance, within a capsule. The surfaces 

 of the plicos communicate with the duct existing along 

 the whole right border of the organ, and are covered 

 with polygonal, organic cells, every one of which con- 

 tains a large, white, round, opaque mass, resembling 

 uric acid in appearance. 



Chapter ix. — on the nervous centres, and the 

 distribution of the nerves. 



The nervous centres consist of three distinct sets of 

 ganglia, which are all placed within the anterior part of 

 the body or head. 



The first set, or supra-oesophageal ganglia, form a trans- 



' See Journal Acad. Nat. Sci. New Series, Vol. I. 



