2i6 Veterinary Medicine. 



the nasal chambers, turbinated bones and (exceptionally) frontal 

 sinuses of carnivora especially : — afo^ (Weisberg, Chabert, etc.), 

 Jox (Monies), wolf (Bremser, Colin, Miram), mule (Greve), 

 horse (Chabert, Leblanc, Rose, Csokor), ^oa^ (Briickmiiller), 

 sheep (Rind), ox (Babes). 



Ovulation. The eggs are ovoid, produced in great numbers, 

 (500,000, I^euckart), and contain partially developed embryos 

 when laid. Expelled by the frequent sneezing of the host, the3' 

 dry, adherent to the vegetation, and are taken in by herbivora 

 with their food and water. They can resist for weeks the influ- 

 ence of atmospheric changes at this stage. 



Embryo. In the stomach the shell is digested and the embryo 

 set free. This has an ovoid body flattened beneath, furnished 

 with two pairs of very rudimentary legs, and on its anterior hook- 

 lets, by the aid of which it bores into the tissues. Its favorite 

 destinations are the mesenteric lymph glands, liver, lungs, pan- 

 creas or other .solid organ. It is destitute of sexual organs, and 

 measures 130/01 long, by 60 /* broad. In its new home it under- 

 goes a series of moultings and passes into the form of agamous 

 larva. In the gland, etc., it quickly loses legs, perforating ros- 

 trum, segments, hooks and hairs, becoming a motionless ovoid 

 pupa, 250 1*. by 180 jn. In about 8 weeks each is seen to contain a 

 nympha, and this is developed into a larva, which largely repre- 

 sents the mature linguatula, except for the absence of generative 

 organs. 



Larva. This is 4 to 8 mm. long, by i to 2 mm. broad anteri- 

 orly. The larva has a fully developed digestive system, two pairs 

 of lateral booklets by the sides of the mouth, and distinct rings 

 dentated sharply on their posterior borders. This form has been 

 known as linguatula denticulatum. Toward the sixth or 

 seventh month, when fully developed as larvae, these migrate, 

 from their evolution-habitat, and pass into other organs (lungs, 

 bronchia) or fall into serous cavities (peritoneum, pleura). They 

 do not reach sexual maturity outside of the air passages so that 

 large numbers perish at this stage of their existence. Sometimes, 

 however, the host is devoured by a carnivorous animal and the 

 larvae reach matiirity in its nasal cavities ; in other cases the larva 

 reaches the bronchia of its first host and makes its way to the 

 nasal chambers to be matured in the same animal. In six or 



