346 Dr Eschriclit"'s Inquiries concerning 



supposed to get through the glottis into the trachea, and, pro- 

 ceeding along its ramifications, at last effect a passage into the 

 substance of the lungs. Other observations, however, make 

 this hypothesis very doubtful, or at least prove that this me- 

 thod of spreading themselves is not the only one. It is well 

 known, that De la Motte (Klein, Hist. Pise. Missus, V^"^' xxv.) 

 and Camper (Krankleithen der Thiere, p. 47) have observed 

 these worms, viz. the Strong, vagans^ in the sinuses of the head 

 of the porpoise. From the description given by Professor Rapp 

 of Tubingen (in his Monography of the Cetacea, 1837, p. 98) 

 of the ear of the porpoise, we might suspect these sinuses to be 

 nothing more than appendices to the cavity of the tympanum ; 

 but this is certainly not the case with them all. Both the 

 Strong, inflexus and vagans are very common in the blood- 

 vessels, the arteries as well as the veins ; and, what is still 

 more important, their presence in the bloodvessels seems to 

 be antecedent to their sojourn in the aerial tube; just as the 

 presence of the Strong, armatus, is antecedent to their sojourn 

 in the alimentary canal. In a young male porpoise, about a 

 year old, I found no worms in the trachea and its branches, 

 a very nire case ; but the lungs were, as usual, occupied by 

 tubercles, in which were small rolled-up worms ; and in the 

 pulmonary artery I found two male Stronggli inflexi, somewhat 

 smaller in size than they usually appear in the trachea, and 

 presenting a very convoluted appearance ; upon which I re- 

 membered, that Professor Baer (Acta Leop. Carol, vol. xiii.p. 2) 

 had found a long worm in the vena azygos, and another in the 

 pulmonary artery of the porpoise, most likely the same Strong, 

 inflexus. The migrations of these worms through the body of 

 the porpoise it may be difficult to ascertain, and the more so 

 as porpoises are rarely to be procured except in spring, when 

 they enter the creeks and bays for the purpose of breeding. 

 But if we compare these observations with those concerning 

 the Strongylus armatus, \he hypothesis will appear probable that 

 the Strongyli in general, pass a portion of their life in the 

 bloodvessels. 



The most important case of the changes of an intestinal 

 worm with which I am acquainted, is that of the Ligulas, 

 otherwise the Bothriocephalus solidus. It is a well-ascertained 

 fact, that this worm, under its former modification, passes a 



