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The Ascaridae 
who have approached the subject, and the limits and contents of the families 
and subfamilies that have been created are very ill-defined. The present 
position, in general, is that the Linnean genus Ascaris has risen to the rank 
of a superfamily, Ascaroidea, with the families Ascaridae, Heterakidae and 
Oxyuridae. These families, again, have been variously subdivided into sub¬ 
families, while there is a tendency, as always in the progress of systematic 
zoology, for the subfamilies themselves to be raised to the rank of families. 
The System of Dujctrdin. 
We may now return to the consideration of the system outlined by 
Dujardin (1845). Having separated off as “subgenera” the forms which now 
compose the families Heterakidae and Oxyuridae from the “true Ascarids,” 
Dujardin places the latter in a “subgenus,” Ascaris , which he further divides 
into four sections, taking the structure of the alimentary canal as a basis for 
the classification. His four sections are as follows (translating as closely as 
possible the original characterizations): 
Section 1. “Ascarids with simple oesophagus with or without ventriculus, 
but without pyloric appendices.” 
In this section are placed the whole of the forms known from mammals, the 
great majority of those from birds, reptiles and fishes, and one from an insect. 
Section 2. “True Ascarids in which the oesophagus is followed by a more 
or less distinct ventriculus and accompanied by a pyloric caecum or appendix 
springing from the intestine.” 
This section comprises the following forms: 
A. gypina Duj. 
Hosts 
Vultures. 
A. depressa Rud. 
Falco, etc. 
A. spiralis (Zeder) 
Owls. 
A. ensicaudata (Zeder) 
Turdus spp. 
A. crenata (Zeder) (prob. = ensicaudata ) 
Sturnus. 
A. heteroura Crepl. 
Charadrius, etc. 
A. semiteres (Zeder) 
Vanellus, etc. 
A. praelonga Duj. 
Colymbus. 
A. crassa Deslongchamps 
Anas, etc. 
A. constricta Rud. 
Trachinus. 
A. incurva Rud. 
Xiphias. 
A. ecaudata Duj. 
Conger. 
Section 3. “True Ascarids in which the oesophagus is prolonged by a 
pyloric caecum or appendix alongside of the intestine, and itself accompanied 
by another caecum springing from the intestine and forwardly directed.” 
Here are placed the following species: 
Hosts 
.4. spiculigera Rud. 
A. pedum Deslongchamps 
A. obtusocaudata (Zeder) 
A. adunca Rud. 
A. clavata Rud. 
Cormorant, Pelican. 
Scomber. 
Salmo, etc. 
Clupea. 
Gadus, etc. 
