the distriliutum (if i:iiliiil nmselcs tlic i-or.iiid t.viie of esoiiliagus 

 may be nmltilnilbai- (Folygaxirophora, Bolbella), creiiate in 

 outline (Pliainiilcnnopsis) or smooth in contour (Oxystomitia, 

 Eiirystomina, Li'ptosomatum) . Among the latter, two tj'pes 

 are distinguishable in regard to the muscular development. 

 In Oxy.slo))iina and its relatives the musculature is poorly 

 developed while in the remaining forms it is well developed. 

 In the Oncholaiminae the esophagus is of a cylindrical t.vpe, 

 the esophageal lining simple, the bnnen also simiile and tri- 

 radiate throughout; the esophago-intestinal valve is triradiate, 

 moderately elongate and contains numerous nuclei. There are 

 12 marginal nuclei but only 2' radial nuclei in Mttniifliolaimus 



liri.itiiirKX and according to their distriliution (Fig. ilO). we 

 may judge that compared with Triin/lii, the third group of 

 radial nuclei (of Metone)wlaimtis} represents a case of fail- 

 ure of cleavage of the last set of radials of the corpus of 

 Tripyla. In the latter form the final cleavage results in the 

 third and fourth sets (Bill and RIV) or 12 nuclei while in 

 Metoncholaiinii.i only six nuclei are present. Likewise the three 

 giant radial nuclei (Fig. 94 OP) of the bulbar region also 

 may represent a cleavage failure. In this form one dorsal 

 and two pairs of subventral gland nuclei are to be found in 

 the posterior part of the esophagus; separate orifices of the 

 two glands in each sector liave not been distinguished. The 



METACMROMADOHA ETMMOLAIMUS 



MtTONCMOLAlUUS EjRrSTOMINA PHA NODEBMOPSIS ANTICOMA LEPTOSOMATUM ENOPLUS 



m 



1} 



^ (^ 



r 



ty (^ 





(It) 



PBIONCHULUS DORYLAIMUS ACAMERMIS 



Vu:. 91 



niuEranis of csophani ini-hiiiing reprcsiintiitivp.'! of ploidiM (.Mfliiiirliiiliiinni.t In Eiiniilim), Ti-ipyluidcii 

 the IJHsmodiiroidca (.M rtiii-hrnniiidora, Monoiio.ilhia) , {Tripyln, I'rinnrlnihis) , Dorylainioidea. Trichuroi 

 rhrcMiiadoroidi-a (KUimoluimus. ilifrnlaiiiniii) , Kno- den und Dioildphyiiiatoidca. OiiEinal. 



88 



