84 ENTOZOA. 



= Cyathostoiiia, Blancliard ; Dochmius, Dujardin ; Prosthecosacter, 

 Diesing ; = Fliarwnis, R. Leuckart ; = Pseudalius, Dujardin ; 

 Stenurus, Dujardin ; Diaphanocephalus, Diesing ; Stephanurus, 

 Diesing ; Deletrocephalus, Diesing ; ? Dicentrocephalus, "Wedl. 



Sclerostoma. — As the best known species of tMs genus lias a 

 special practical interest in relation to the development of the 

 gape-disease in fowls, I shall here offer a rather particular account 

 of its history, structure, and development. 



In the year 1799, a letter from Dr. Andrew Wiesenthal, Pro- 

 fessor of Anatomy at Baltimore, U. S., was published in the second 

 volume of the " Medical and Physical Journal," containing an 

 account of a parasite infesting the trachea of fowls and turkeys 

 in America. As this brief communication bears the early date of 

 May 21st, 1797, and constitutes the first public record that we 

 have respecting the above-named entozoon, I will introduce the 

 subject by a short extract from Dr. Wiesenthal' s letter. " There 

 is," he says, "a disease prevalent among the galhnaceous poultry 

 in this country, called the gapes, which destroys eight-tenths of 

 our fowls in many parts, and takes place in the greatest degree 

 among the young turkeys and chickens bred upon old-established 

 farms. Chicks and poults, in a few days after they are hatched, 

 are found frequently to open their mouths wide and gasp for 

 breath, at the same time frequently sneezing and attempting to 

 swallow. At first the affection is shght, but gradually becomes 

 more and more oppressive, and it ultimately destroys. Very few 

 recover; they languish, grow dispirited, droop, and die. It is 

 generally known that these symptoms are occasioned by worms in 

 the trachea. I have seen the whole [windpipe] completely filled 

 with these worms, and have been astonished at the animals being 

 capable of respiration under such circumstances." 



Any one who has witnessed birds suffering from the above- 

 named malady, known in this country also by the name of gapes, 

 will at once have recognized the close accuracy of Dr. Wiesenthal' s 

 description ; and, so far as the phenomenology of the disease itself 



