piri-li" i-oiisists of ton papillae. Tlu'io ia a distinct toiidenc.v 

 tinvanl fusion of papillae with eoiiieident leduction in size of 

 the dorsoilorsals, ventrolaterals and ventroventrals the median 

 pairs of the external eirele hein^ nearly eonii)letely fused in 

 Sti i>liiiniiru.i (liiitdliis, partially fused in Siiiiiiaiiniii travhia 

 and separate but approaehinj; in pairs in Dchtroci pUaUis ilemi 

 iliatiix. As in the Stron);ylidae the laliial region is usiuilly set 

 off liy a Ki'oove hut unlike the StrouKylidae, the nu'dial papillae 

 of the external eirele are never in the form of duplex setose 

 papillae ( Fig. ."ill). 



The family Aneylostomatidae is eharaeterized by the absenee 

 of both lips and a eorona radiata; instead the oral opening 

 is nuxlified to the funetion of i>rost(Mnatal teeth or eutting 

 edges. .\s exeinplilied by Nccalor ami ricanns the full eom 

 ponent of papillae are represented, all of them being reduced 

 with the exeeption of the laterodorsals and lateroventr.nls and 

 one finds the nu'dial pairs of the external eirele elosely ap 

 proximate as in the .Syngamidae. The labial region is not 

 set off by a groove as in the previously mentioned families. 



The family Diaphanoeephalidae is eharaeterized by a dor 



soventrally elongate oral o|U'ning and is without lips, leaf 

 erown, |irostoniatal teeth or eutting edges. The full eomponent 

 of papillae is represented, there being an internal eirele of 

 six reilueed jiapillae and an external eirele of four incuni 

 pletely fuse<l subnu'dial and two simple ventrolateral (Kali- 

 ci'plialiis sp.). 



The family Cloaeinidae is partieularly noteworthy becau.se 

 of the presence of six massive lips, the laterals somewhat lower 

 than the subuu'di:ins. In Zoniotaimu.t svtiffra the internal 

 circle is represented by reduced internolaterals and the external 

 circle by four ( ! duplex) conoid ijapillae. 



Trirhnsl rifnf/i/hii'tra. Kepi'esentjit i\'es tif this superf:imily 

 often have a dislinet ceiihalie inllation or cuticular helmets of 

 numerous si)eeiali/.ed forms which are used as generic charac 

 ters. They are always devoid of a leaf crown and seldom 

 show rudiments of either six or three lips. The oral opening 

 may be of diverse form but is nearly always surrounded by 

 an inconspicuous eircumoral membr.-ine. Kepresentatives 

 studied by the writers have an internal circle of six reduceil 

 papillae and an external circle of 10 simple i)apillae (medials 



Ceijh;ili<- regions in the Khaljditnidea. AC — RlijilMiilidae. ])- 

 M — DtploEiisteridne. N-0 — Ithutidin.sidne. P — .Strongyloididae. 

 Q — Angiostoiiiatidjie. R-S — Orilonematidae. T — Steinernenia- 

 tidae. L'-V — (.'ylindrogasleridae. W-.\A — Cephalobidae. A — 

 JibnhilitiM terrirntn ; B — Khnbtlith anpfra; (' — Dipliinrapter ror~ 

 tintttn ; 1) — Ithiihililiiloidps sp. ; E — Arrostwlnis tnletlni; F — Ly- 

 cnloimtm ilifriniji ; (J — Odontopfiarj/rur lonpifiimlfitii ; II — AUoin- 

 nfwu apprntUcultitum v. duhitt : I — PyitiHoneltun tifrirora ; J — 

 JtiplujfitMter prttir ; K — Monont'hoitl^/t ii iiieririinnn ; 1. — Tj/tn- 

 phnriinx Mtrinta; M — HutleritiH htitleri; N — Entoiiielan etitomf- 

 lag; (> — RhnhtlutH i>n»lrepton ; P — St rnni/ylnidftt rantmmi ; Q — 

 Artffiostotnii plethndontiji : K — Unijella ttfcta; S — Dirfilis nira ; 

 T — Xeoaplfrlnnn i/taxeri ; U — Ci/lindrofftt^ler ; V — Lnnj/ibuct-a 

 Ifmiura: \\ — Cfphatahns pprHfjjnix : X — Pnii/ijjrnluiwtiM vuhf- 

 lonytittiM : Y — Xrn3}iplfs rtnnith-.rns ; Z — VhdtiiberHieUft ntdens ; 



.\.\ — Acrobetoideil butschlU. K-K — After Rahm. 1929. Arc-li. 

 Inst. Biol. V. 2. G — After de Man, 1912, Zool. Jahrb. .\bt. Sjst., 

 V. 33 (6). 11— After Chitwood and Mcintosh. 1934, I'roc'. Helm. 

 Soi-. Wash. V. 1(2). I — .\fter .Sti-iner. 1934. Proc. Helm. Soc. 

 Wash., V. 1(2). L-M — After Goodey, 1929, J. Helminth., v. 

 7(1). P — After Alicata. 1935, U. S. I). A. Tech. Bull. 489. 

 R — After Cobh, 1928, J. Wash. Acad. Sc, v. 18(7). S — After 

 Chitwood and Lucker, 1934, Proc. Helm. Soc. Wash., v. 1(2). 

 T — After .steiner, 1929, J. Wash. Acad. Sc. v. 19(19). U — 

 After Steiner. 1933, .1. Parasit. v. (20(1). V — .\fter Mcintosh 

 and Chitwood, 1934, Parasit. v. 26(1). W-X — After Thorne, 

 1937, Proc. Helm. Soc. Wash. v. 4(1). Y and AA— After 

 Thorne, 1925, Tr. Am. Micr. Soc. v. 44(4). Z — After Cobb, 

 1920, Contrib. Sc, N'emat. 9, Remainder original. 



57 



