402 ENTOZOA. 



since repeatedly detected this parasite in the livers of negroes at 

 Cairo ; himself and Von Siebold having made it the subject of 

 careful study. All that need here be said concerning it may be 

 summed up in a very few words : — It differs from the larval form 

 of Pentastoma toenioides {i. e. from the so-called P. denticulatum) in 

 not being furnished with any integumentary armature of spines, and 



Pio. 81. — The Pentastoma constrihtum. (Magnified four diameters.) — Bilharz. 



in the additional circumstance of its being a much larger worm. 

 The cephalo-thorax is well marked, ftirnished with four foot-claws, 

 and distinct from the elongated abdomen, which displays twenty- 

 three rings or constrictions at tolerably regular intervals. The 

 anterior extremity of the animal is rather obtusely rounded off, 

 the caudal end being bluntly conical. It attains a length of rather 

 more than half an inch, whilst the breadth scarcely exceeds a 

 single line. 



