37O ARTHUR C. WALTON. 



1. Material used is same as recognized European forms of 

 Ascaris canis (Werner) and Ascaris felis (Goze). 



2. A. canis shows 18 chromosomes for the haploid number, 

 12 di-tetrad autosomes and 6 tetrad idiosomes. These 6 tetrad 

 idiosomes form a heterosome group of the X-type. 



3. There are two types of second spermatocytes and spermatids 

 found, one type having 12 autosomes and 6 idiosomes, the other 

 type having but the 12 autosomes. 



4. In A. felis there are 9 chromosomes in the primary spermato- 

 cytes, 8 autosomes and one large heterochromosome composed 

 of unequal parts. This is in agreement with Edwards. 



5. A. canis and A. felis are morphologically and cytologically 

 two different species, not varieties of the same species. 



6. Chromosomes of true A. canis do not agree in form or num- 

 ber with those described by Marcus for his "so-called" A. canis. 



BIBLIOGRAPHY. 

 Boveri, Th. 



'09 Ueber Geschlechtschromosomen bei Nematoden. Arch. f. Zellf., Bd. IV., 



Hft. i, pp. 132-141. 2 Textfiguren. 

 Edwards, C. L. 



'n The Sex-Chromosomes in Ascaris felis. Arch. f. Zellf., Bd. VII., Hft. 3, 



PP- 309-313- Plate XVII. 

 Glaue, H. 



'08 Zur Unterscheidung von Ascaris canis und A. felis (Ascaris canis s. mystax). 



Zool. Anz., Bd. XXXIII., Nr. 24, 25, S. 785-790. 3 Textfiguren. 

 '09 Beitraege zu einer Monographic der Nematoden species Ascaris felis und 

 Ascaris canis. Zeitschr. wiss. Zool., Bd. 95, Hft. 3, S. 551-593. 26 Text- 

 figuren. 

 Marcus, H. 



'06 Ei und Samenreife bei Ascaris canis (Werner) (Asc. mystax). Arch. Mik. 

 Anat., Bd. LXVIII., Hft. 3, S. 441-491- Taf. XXIX-XXX. 10 Text- 

 figuren. 

 Schneider, A. 



'66 Monographic der Nematoden. S. 34-39. i Textfigur. 

 Schoeppler, H., and Krueger, P. 



'12 Zur Unterscheidungsfrage von Ascaris canis und Ascaris felis (A. canis s. 

 mystax). Centralbl. Bakt. Parasit., Abt. i, Orig. Bd. LXIL, S. 143 146. 



