BUREAU OF ANIMAL INDUSTRY. 557 



the miscroscope large numbers of eggs and living embryos are also 

 found. These nodular elevations have been described by other authors 

 in connection "with various forms of verminous bronchitis, but it now 

 seems probable that they are produced by but one kind of parasite 

 {Pscudalius ovis j^ulmonalis). 



DESCRIPTION OF THE PARASITES. 



The lung-worm of cattle is described by Sclmeider [MonograpMe dcr 

 Ncmatoden) as follows : 



Strongylus micrurus, Melilis. — Male, 35"^"^ (1.4 iucLcs) ; fouuile, CO"'""' (2.4 inches) 

 nioutli round, witliout noticeable papilUe ; cuticle smooth; vulv.-i IS""" (.7 inch) from 

 caudal ostrcmity. Viviparous. Bursa small, round. Posterior ray.s three notches of 

 tho extremity of the common trunk. Middle rays single. Anterior rays separate. 

 Spicula short and strong, colored deep brown. 



A number of lung-worms received recently at the laboratory from the 

 West were raeasuEcd and of three of the adult males the dimensions were 

 40"™, SO""™, and 53""", respectively. This Avould make the average 

 length at least 45™'" (1.8 inclies). Two adult females measured 55™™ and 

 G5""", respectively. Tho -width of the body in both sexes was from .4™»" 

 to .5'"™ (.015 to .02 inch) ; the ova within the uterus, and containing ma- 

 tured embryos, were .08""" long and .05"^™ wide. (For drawings made 

 from these specimens, see Plate Y, with description.) 



Tho' stroiujyli removed from the lungs of the calf at the experimental 

 station were found somewhat shorter. Of ten males the average length 

 was about 37'""' (1.5 inches) ; ten females averaged about 47'"'" in length, 

 or almost 2 inches. The embryos of the lungs measured about .3°"" in 

 length (about .012 inch) and .OlS'""^ (.0007 inch) in thickness. Those 

 hatched from ripe ova a day later were of the same dimensions. The 

 ova were about .05""" (.002 inch) wide and .OO'""' (.0036 inch) long.* The 

 adult worms within the bronchi were kept for at least forty-eight hours 

 in the refrigerator at a temperature of 50=^ to 55^ F., and very few mani- 

 fested any movements. After a few hours' sojourn in a normal salt so- 

 lution in the incubator at a temperature of 98^ to 100^ F., mo.st of them 

 exhibited very active movements. A large number of ripe ova were 

 placed in temi)eratures of about 50'^, 05^, and 75<^ F., respectively; within 

 twenty-four hours very few of the embryos of the tirsr, lot had left the 

 shell, while a large number wore found hatched and livelv in the third 

 lot. 



The most common lung- worm of sheep is described by the same author 

 as follows : 



Strongylus fiJaria, R. — MaleSS""™ (linch). Female 70™"" ('3. 75 inches). Mouth round. 

 Head rounded, -without noticeable papillaj. Cuticle ^ith numerous longitudinal 

 ridges. Yulva 30""™ (1.2 inches) from tho caudal extremity. Ovaries symmetrically 

 directed, anteriorly and posteriorly. Uterus filled Avith free embryos. Bursa long. 

 Three dorsal rays, also shallow notches. Ventral rays separated. Spicula sliort and 

 very thick, dark i)rown. (Plate VI, Figs. 5 and G.) 



These two species are very closely related, bat are definitely distin- 

 guishable by tho different situation of the vulva, and the absence of all 

 cuticular ridges in the former. 



The oesophagus of Strongylus filaria is about 1.5"'°* (.00 inch) long, with 

 a bulb-like enlargement at its junction with intestine into which its bell- 

 shaped terminal portion projects. The intestine extends as a brownish 

 tube through the entire body. The vulva shows as two projecting lips. 



*Th6 discrepancy in length between this and the other lot of ova is explained wlien 

 •wo consider that the former were measured fresh. 



