METONCHOLAIMUS PRISTIURUS (ZUR STRASSEN) 



A Nema Suitable for Use in Laboratory Courses in Zoology 1 



BY N. A. COBB 

 CONTRIBUTIONS TO A SCIENCE OF NEMATOLOGY XXV 2 



Zur Strassen, who first proposed the species Metoncholaimus pristiu- 

 rus, alluded for the most part only to the organs whose forms served 

 to distinguish it from its nearest allies among the oncholaims. The 

 present attempt at a more complete understanding of its morphology 

 adds to our knowledge in a number of ways, especially with regard to 

 the remarkable demanian system. 



At the same time the text and figures have been prepared with par- 

 ticular reference to requests of school, college and university instruc- 

 tors in invertebrate zoology, a course suggested by the fact that this 

 species has been used with some promise of success in the invertebrate 

 courses of a considerable number of universities. 



Unfortunately few if any zoological textbooks treat nemas ade- 

 quately. It is believed that any progressive and well equipped in- 

 structor who will study carefully the following descriptions, with the aid 

 of good living as well as preserved specimens, will find himself all the 

 better equipped to instruct students concerning the morphology of 

 the important nemic phylum. 



METONCHOLAIMUS PRISTIURUS (Zur Strassen) 

 [Meta, changed; Oncholaimus, tooth (in the) throat] 



FEMALE. Fig. 1. 



The cuticle and the body wall. olii "/" i.i \A i.s o.z* 5 - 6mm 



The contour of the nema is plain. The thin, transparent, colorless, nearly 

 naked cuticle, 72, 96, about one micron thick, is traversed by plain transverse 

 striae; but these are very difficult of resolution except with high powers of the 

 microscope used skillfully under favorable conditions, ordinarily they will 



1 Through the much appreciated courtesy of the United States Bureau of Fisheries a 

 considerable part of these investigations was carried out at its Laboratories at Woods 

 Hole, Mass. Received May 18, 1932. 



2 Reprinted from the JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES, Vol. 22, 

 No. 12, June 19, 1932. 



Warerly Press, Inc., Baltimore, Maryland, December, 1932. 



