CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 105 



in an inflamed condition. These entozoa, acting finally as an obstacle 

 to the passage of air, produced death by asphyxia. 



Wiesenthal did not occupy himself with the specific determination of 

 the worm, but Montagu regarded it as a distome, a fasciola (fluke) of a 

 particular kind, having a round cylindrical body with two sucking 

 disks, borne on two peduncles of unequal length. 



Rudolphi* and the authors of his time continued to regard the cause 

 of the gapes in the gallinaceans as a distome, and included it in the spe- 

 cies JDistoma lineare (Rud). 



Shortly after, helminthologists discovered, ui)on a variety of birds, a 

 curious parasite likewise inhabiting the trachea, but this time belong- 

 ing to the order of nematodes, and especially characterized by the sin- 

 gular habit of permanent union of the sexes. Siebold t made it the type 

 of a new genus— the genus Syngamus ; later, however, yielding to the 

 observations of Kathusius, he renounced his first idea and united this 

 helminth with the strongyli in imming it Strongylus tracliealis.X 



After the creation of the genus Sclerostoma by Dujardin, in which this 

 author unites the old strongyli possessing a month which is armed with 

 a tough coriaceous capsule, Diesing ])\siced in it the Strongylus tracheaUs 

 of Nathusius under the name of Sclerostoma syngamus. Finally Dujar- 

 din § restored for this parasite the old genus Syngamus of Siebold, and 

 gave it the old specific name of Syngamus trachealis of the same author. 



Dujardin ascribes to the genus Syngamus the following characters : 



Worms ordinarily coupled in a permanent manner or by union of the integuments ; 

 the male, cylindrical, much smaller than the irregularly cylindrical female, with con- 

 stricted neck and tail tapering to a point ; head globular, large, supported by an in- 

 ternal corneous capsule ; mouth large, irregularly rounded, with six or seven broad- 

 ened lobes; pharynx provided with tleshy papilht* ; integument folded or wrinkled 

 without regular stri:e. The male has a truncated tail, the latter pi-ovided with a mem- 

 braneous expansion which fastens itself to the integument of the female. The female 

 has the tail conical, elongated ; vulva situated anteriorly at the base of the constric- 

 tion forming the neck ; eggs large, elliptical. 



The following, according to the same author, are the characters of 

 the only species Syngamus trachealis, which this genus includes : 



Body soft, colored bright red hy a liiiuid interposed between the viscera. ]\Iale 4 

 to 4.5™'" (.157— .177 inch) long; .4"™ (.016 inch) wide ; enlarged, obliquely truncated 

 head about .7'"'" (.028 inch) broad. Tail terminated obliquely by a convex, unilate- 

 ral, membraneous sac or bursa .25 to .3""" (.009 to .012 inch) long, attached to the 

 8ui)erior border of the vulva of the female and supported by 12 to 15 equal rays. Fe- 

 male 13""» (.512 inch) long ; .3 to 1'"™ (.01 to .04 inch) broad, irregularly folded and 

 wrinkled; head 1.3""" (.05 inch) broad; tail resembling an elongated cone; anus 

 1.2"'"' (.047 inch) from extremity ; projecting vulva at the base of a neck 1.5 to 2""" 

 (.058 to .08 inch) long, inclined to one side; eggs smooth, elliptical, .087 to .093"'"' 

 (.0034 to .003(5 inch) long, with a short terminal neck. 



*Synops. pp. 414, 415. 



\ Archiv f. Naturf/eschichte, Wiegmann (1835), p. 1. 



tL. c, 1830. 



v\ nintorei iiat. den livlininthefi i» suiten a Bnffo)i. Koret, Paris, 1845, p. 200. 



