406 PARASITES OP ANIMALS 



tion to lumbricoid endemics must at once be obvious ; I have 

 already, however, dwelt upon this subject when treating of the 

 human parasites. In like manner, the subject of the flesh- 

 worm disease, which is due to Trichina spiralis, cannot be 

 discussed in this place, as I have fully entered upon it in 

 connection with trichinosis in the human subject. What may 

 be the nature of the small threadworms found by Leidy in the 

 extensor muscles of the hog I cannot say, but Diesing inferred 

 that they might represent a distinct species (Trichina affinis). 

 As regards the allied genus Trichocephalus, the common species 

 infesting swine (T. crenatus), appears to be rarely absent. It 

 not only infests the common domestic and wild hog, but the 

 peccaries and wart-hogs. These entozoa are probably harmless 

 to their bearers. In reference to them Krabbe says : " When 

 the eggs are expelled with the excrement and pass into water, 

 then the embryos, after several months' furlough, and there 

 undergoing further development, are transferred to the swine's 

 intestinal canal." If I rightly understand the paragraph 

 (' Husdyrenes Indvoldsorme,' p. 28), Krabbe states that the 

 embryos are still within their egg-coverings when infection 

 takes place. The maw-worm of the hog is known as Spiropiera 

 strongylina. It was described and figured by Gurlt. The 

 males measure J" and the females |" in length. Specimens 

 of this worm were supposed to have been found by Natterer in 

 Dicotyles albirostris ; but it seems that the worms in question 

 represent a distinct species, if not an altogether new genus. 

 In the year 1864 Professor Simonds placed in my hands a 

 very singular nematode, to which I gave the binomial term 

 Simondsia paradoxa. Numerous examples of this worm were 

 found by Prof. Simonds occupying cysts within the walls of 

 the stomach of a hog which had died at the London Zoological 

 Society's Menagerie. In my introductory treatise I wrote of 

 it as follows : " The worm in question has been regarded by 

 Mr Simonds as a species of Strongylus, but I am inclined to 

 think that its affinities will place it nearer to the genus Spiro- 

 ptera. At present I have only examined the female, which is 

 characterised by the possession of a multitude of large tentacle- 

 like * appendages surrounding the neck. These processes, by 

 their aspect, remind one of the so-called branchial projections 

 on the back of Eolis, but in this worm I believe them to bo 

 special folds formed for the lodgment of unusually developed 

 uterine organs. The female worm is about }" in length/' 



