72 ENTEEOBIUS (OXYURIS) VERMICULARIS 



K. Family Oxyuridae 



Small to medium sized forms; cuticula thickened on each 

 side for the whole length of body in the form of a lateral 

 flange or wing; esophagus long with a well marked bulb 

 containing a valvular apparatus; tail end of female drawn 

 out into a long point; eggs asymmetrical; males much smaller 

 than females, with one spicule. 



Enterobius vermicularis (Oxyuris vermicularis) (Plate 

 VIII, Figs. 5 and 6). Pin worm; color white with striated 

 inflation of the cuticula at the anterior end; male 3 to 5 

 mm. in length; posterior extremity of body is curved ven- 

 trally and has six papillae; single spicule, about 70ju long, 

 hooklike; female, about 10 mm. in length; anus 2 mm. 

 from tip of much attenuated tail; vulva in anterior third 

 of body. Adults in large intestine of man; young forms in 

 posterior part of small intestine and often appendix; infec- 

 tion direct without intermediate host; time of development 

 of larvae in eggs required outside of host very short; in 

 large numbers may produce enterocolitis and appendicitis 

 small numbers produce irritation; distribution cosmopolitan. 



An oxyuris like egg has been found in fecal examinations 

 to which the name Oxyuris incognita (Plate V, Fig. 20) has 

 been given. Nothing is known of the adult to which this 

 egg belongs. Recently Syphacia obvelata, a mouse oxyurid 

 has been reported incidentally from man. 



