Leuckart saw in his aquarium young Cucullani penetrate into the bodies of the cyclops. These crustaceans are therefore the vehicle of these nematodes. Another nematode worm, the Dochmius trigonocephalus, lives at liberty while young, but seeks for an asylum in the dog in its old age. The Sclerostomum equinum causes aneurisms in the horse, which manifest themselves by colic. A hundred of these worms have been found in the same horse. The Sclerostomum pinguicola is very common in the pig in the United States. This is the Stephanurus dentatus of Diezing, noticed by Natterer in Chinese pigs in Brazil. Cobbold notices the same worm as living in the pig in Australia; they have been also found in Germany.
The Strongyli are round, cylindrical worms, with bodies sometimes entirely red, which inhabit different
organs in mammals and birds. A very remarkable species, the Strongylus gigas ([Fig. 66]), exists in the kidneys of the horse and the dog, and sometimes in man. It partly destroys this organ, and has been seen a mètre in length. The Strongylus commutatus often lives in great abundance in the lungs of the hare, and the Strongylus filaria in the lungs of the sheep, occasionally in such great numbers that their presence produces pneumonia.
Fig. 66.—Strongylus gigas.—1, female, showing a, the mouth; b. the intestine; c, genital pore; d, anus. 2, cephalic extremity of the male; a, mouth; b, œsophagus. 3, caudal extremity of the male; a, cup; b, penis. 4, egg.
Porpoises generally have strongyli in their lungs and their bronchia, and they are seen by thousands in the
sinus of the Eustachian tube. We collected a large bottle full from a single porpoise around its internal ear. When we consider the prodigious number of these creatures, may we not suppose that they are able to multiply in the organs which they occupy, as well as migrate to infest other individuals.
Different generic and specific names have been given to these Strongyli. A round worm found in the intestines of the dog, the Strongylus trigonocephalus, lives at first in damp earth or mud like the rhabdites in general; it then passes into the dog, and there becomes a sexual Strongylus. It is possible that there are others in the same category.