58 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



EXPLANATION OF PLATES 

 Order ENOPLATA 



Pl. I, Fig. i. Mononchus trichurus Cobb, the female showing some typical 

 characters of the order. Note the smooth cuticle, the plain 

 bulbless esophagus, and the female genitalia with the re- 

 flected ovaries, a, top of ovary; b, base of ovary; c, ovi- 

 duct ; d, e, top part of uterus transformed into a receptacu- 

 lum seminis with sperm inside; /, egg in the main part of 

 the uterus; g, genital opening; in typical cases there are 

 two ovaries. After Cobb, 191 7. 



Fig. 2. Leptosomatum bacillafiim (Eberth) showing the typical head 

 structure of the Enoplidae. Note the wide surface by 

 which the esophagus attaches to the cuticle anteriorly, the 

 duplication of the cuticle with the "circumoral pocket" be- 

 tween the two layers, and the pocketlike amphid. After 

 Filipjev, 1918. 



Fig. 3. Thoracostoma coeciim Saveljev, showing an example of a 

 highly developed cephalic capsule. After Filipjev, 1927. 



Fig. 4. Enopliis communis Bastian, showing the head viewed from 

 the side and a little ventrally. Note the three typical jaws, 

 surrounded by the ring of the cephalic capsule, the amphids, 

 and the cephalic organ anterior to them, the cephalic line. 

 After de Man, 1886. 



Fig. 5. Enoplus communis Bastian, showing the head viewed en face. 

 Note the typical disposition of the 10 cephalic setae and 6 

 labial papillae ; note also the symmetrical disposition of the 

 3 jaws. After de Man, 1886. 



Fig. 6. Enoploides amphioxi Filipjev, a head showing the jaws split 

 behind, the lips highly developed, and the setiform labial 

 papillae. After Filipjev, 1918. 



Fig. 7. Enoplolaimus hicifer Filipjev, showing the head with the jaws 

 transformed in a framework of the mouth capsule, and an 

 onchium between the two posterior prolongations. Note 

 the cephalic organ pointing externally. After Filipjev, 1927. 



Fig. 8. Oxystomina elongata (Biitschli), showing the elongated head, 

 the four sublateral setae shifted backwards to form a sec- 

 ond circle, and the amphid very far behind and with an en- 

 larged orifice. After de Man, 1907. 



Fig. 9. Halalaimns diplocephahis Filipjev, showing the amphids elon- 

 gated to form a longitudinal slit. After Filipjev, 1927. 



Fig. 10. Phanoderma conicaudatiim (Steiner). Note the four-lobed 

 cephalic capsule, the eye with a well-defined lens, and the 

 far-advanced cervical pore. After Filipjev, 1927. 



Fig. II. Oncholaimus conicauda Filipjev, showing a typical mouth cap- 

 sule with three onchi and the "circumoral pocket". After 

 Filipjev, 1929. 



Fig. 12. Rhabdodemania major (Southern). Note that the mouth 

 capsule with three onchi is comparable to that of the On- 



