ASCARIS CANIS AND ASCARIS FELIS. 365 



MATERIAL AND METHODS. 



The material used was obtained from freshly killed dogs and 

 cats. The worms were immediately removed from the intestine, 

 placed in normal salt solution and kept at body temperature 

 until they could be fixed. The ovaries and testes were at once 

 stripped out on a glass plate and fixed. Hermann's fluid and 

 Flemming's fluid (strong) were used to fix the testes, and Pe- 

 trunkevitch's modification of Gilson's fluid was found to be the 

 most satisfactory fixative for the ovaries. Sections of the 

 testes were made 4 M to 8 ju in thickness; those of the ovaries, 

 10 /z to 30 fjL in thickness. In general the material was stained 

 by a modified iron-alum-hsematoxylin method: dilute Dela- 

 field's hcematoxylin being used in the place of ^ per cent, aqueous 

 solution of haematoxylin after the mordant. This method gave 

 better contrast between the chromatin matter and the yolk 

 granules than could be obtained by the ordinary Heidenhain 

 method. Orange G and Bordeaux Red were used as counter 

 stains. 



TAXONOMIC COMPARISON OF A. CANIS AND A. FELIS. 

 Anatomical study of one hundred specimens of A. canis and 

 fifty specimens of A . felis gave the results shown in the following 

 table. The table at the same time gives a comparison of the 

 main points of difference between the two forms. 



A. canis. A. felis. 



Length of animal 60-120 mm . -45-95 mm - 



Length of oral wing 1,950-2,250 mm 1,450-1,720 mm. 



Breadth of oral wing 350-500 mm 400-600 mm. 



Shape of oral wing Lanceolate Cordate. 



Cross-section, oral wing . . .Chitinous rod, long and Chitinous rod, broad and 



narrow. flat. 



Wing spicules Long, crescent-shaped . . . .Long, semi-circular. 



Form of tail of male Gradual slope to point. . . .Folded ventrad to point. 



Postanal papillae 4 ventral, 3 dorsal pairs. . .3 ventral, 2 dorsal pairs. 



Anal spicules Short, narrow Longer, broader. 



Body segments Narrow Broader than A . canis. 



From this comparison it is seen that A. canis is longer than 

 A. felis and has an oral wing which is lanceolate rather than 

 cordate in shape (Text-figs. A and B). Cross-sections of the 

 oral wing show differences in the shape and size of the supporting 



