METONCHOLAIMUS 83 



reproductive system. It consists of the following structures 

 — the moniliform glands, two large, clear, cross-striated tubes, 

 lying a short distance anterior to the rectum. These glands 

 open posteriorly by separate pores. Anteriorly these tubes 

 unite near a very obvious structure, the rosette. From the 

 rosette a tube runs to the intestine, and another tube, start- 

 ing as a wide ampulla, soon narrows rapidly to form a thin 

 tube, which joins the uterus in the vicinity of the vulva. 



Make a large drawing of a female Metoncholaimus to 

 show as many of the above features as you have been able 

 to make out. If possible make also diagrammatic cross sec- 

 tions of the body (1) in the region of the esophagus and nerve 

 ring (2) in the midovarian region and (3) through the monili- 

 form glands. 



The Male Metoncholaimus. — In the manner already de- 

 scribed mount several specimens as large as the female but 

 showing no eggs. These are probably males. Compare the 

 posterior end with that of the female. Do you find any trace 

 of the demanian system? The opening of the male genital 

 system is just anterior to the anus. Two slender rodlike 

 spicula may be seen running forward from it for some dis- 

 tance. Anterior to the spicula is the ejaculatory duct, which 

 is connected with the vas deferens. The latter is usually 

 difficult to see. Careful focussing in the midregion of the 

 body will enable one to see the clear, colorless cells which 

 constitute the elongated testes, one anterior and one posterior. 

 In each testis there is a progression of stages from before 

 backward. A study of the length of this organ will show 

 spermatogonia and all stages in spermatocyte growth. Occa- 

 sionally mitotic figures are observable. 



Make a drawing of the male Metoncholaimus. 



