new Siamese Nematode. 



411 



rest more ventrally. The spicules (figs. 3-5, S.) are equal 

 in length. They are wide dorso-ventrally, sickle-shaped, 

 with a finely striated surface, and each presents much the 

 appearance of having- a smaller tubular spicule enclosed 

 within it. There is an accessory piece (figs. 3-5, A.P.), 

 granular in appearance, and with a median projection which 

 lies between the spicules near the cloacal opening. 



Fia:. :;. 



Falcaustra siamensis. Caudal end of male, lateral view. 



A. P., accessory piece; CI., cloaca; D.Ej., ejaculatory duct; Int., in- 

 testine; R., retractor muscle of spicule; S., left spicule; Su., 

 sucker-like organs; V.S., vesicula seminalis; 1-11, papillae. 



The female genital organs are similar in arrangement to 

 those of F. falcata. The vagina runs forward and dorsally 

 for a distance of about 2 mm. from the vulva, gradually 

 expanding into a thick-walled muscular chamber with a 

 maximum diameter of 0'45 mm. It then gives off two 

 opposed uteri. The anterior uterus runs forward to a point 

 about 3 mm. from the junction of oesophagus and intestine, 



