558 REPOKT OF THE COMMISSIONER OF AGKICULTURE. 



Very cliaracteristic are the two hollow, dark spicnla, about .5"^^ (.02 

 inch) long ; eggs, oval, .I'"'" (.OOi inch) long, .00 ""'^ (.024 inch) broad. 

 Embryos .5'"'" (.02 inch) long, and .02"^"^ (.0008 inch) in diameter. Tail 

 slender, slightly curved, pointed. The head has a characteristic cup- 

 ular projection. 



Tlie hmg-worm, found frequentl^^ in pigs ^\ithout causing much dam- 

 age, but also in sheep, where it is said to canse at times severe bron- 

 chitis, deserves on this account a passing notice. It is briefly described 

 as follows {loc. cit.) : 



Slrongylvs paradoxna, MeL lis.— Male 20™'" (.79 iuch). Female 30""" to 35""" {Iri 

 inclios, to 1.28 iuch). Mouth surrouiicled by six lobes. Tlie two latenil ones lar<(o.st. 

 Vulva uear auus projecting, surrounded by a vesicle or bladder-like body, vi.siblc to 

 the naked eye. Caudal end of male, at the base of bursa, curved toward the ventral 

 aspect. Bursa with numerous folds; it cannot be spread without tearinj^, hence no 

 desciiptioi) possible. (Plate VI, Fi^s. 1 and 2.) 



Tlje male is provided with two very long s])i<;nla, jneasuring 2.5'""' (.1 

 inch) ontside of tlie body. They are hollow, tubular, and neatly nmrked 

 with transverse V)ands. 



The hair-worm (Plate ^ i, Figs. 3 and 4) which produces the tubercular 

 iu)(lules on tlie surface of the lungs in shee]) [Ptiendaliufi avis pulmoiialis) 

 may be briefly described as cylindrical in shape, 20'""' to 30'""^ (.79 inch to 

 1.2'inch) long, .05""" to .07"'°' (.002 inch to .0028 inch) thick, the female 

 being longer than the male. The caudal portion of the body of the 

 male is wound up in close spimls ; that of the female is wavy. Mouth 

 corolla shaped, v>'ith four membranous li[>s. It contains a boring apjia- 

 ratus resembling a fir cone. The caudal end of the male is cleft and pro- 

 vided with two ecjual, arche<l, dark-brown spicules. The free cml of each 

 is divided into two sjiiiies, toothed ventrally. This latter worm may be 

 rea<lily distinguished from the oth.er forms described by its attenuated 

 ibrm, the absence of a distinct buisa and the bilid sjiicules. IStronr/i/his 

 paradoxus is readily singled out by its peculiar bladder-like attachment 

 in the female, and the very long, hooked spicnla in the male. The re- 

 maining two species {Strongylusmicrurus and iStrongi/lus fdaria) are very 

 much alike, but (he habitat will serve as a means of distinction, if the 

 microscopical cliaracters cannot be studied. 



The complete life history of the various lung-worms is still a matter 

 of siieculation among helminthologists. ^A thorough knowledge of the 

 mocle of life of the embryos and lar\ie before their final establishment 

 in the trachea of domestic animals would guarantee better means of 

 prevention. 



In regard to the Strongylus filaria of sheep, Leuckart describes the 

 ead>ryos discharged with .the mucus as quite well characterized by a 

 button-like iirojection at the cephalic extremity. They remain alive in 

 moist earth for weeks. They may even dry out and still assume their 

 activity on the addition of water. They molt in about two weeks, and 

 die soon after. Laml)s fed with molting embryos failed to take the dis- 

 ease. Fourshee}) fed at different times v/ith bronchial mucus contain- 

 ing numerous embryos, remained well. Leuckart, therefore, concludes 

 that the embryos, after being discharged from the lungs, probably in- 

 vade some invertebrate, such as insect or snail, aiul theie attain twice 

 their original length before they are capable of becoming matured when 

 taken up by ruminants. He does not share the views of some Avho main- 

 tain that the disease is communicable directly from one animal to an- 

 other. In other words, the contact of the sick with the healthy is not 

 dangerous. 



Most of the authorities of to-day seem to accept this yiew, and it cer- 



