not have I'oiivorfjiiiir walls. In all instances tlio iiiesorliahilions 

 are divided into twci or more elements to their base. In true 

 ehoanolainis {Ilnlirhniiiinliiiinns ilolichitnts, (iom nutncintt ftrox) 

 the |ii(islom is like an inverte<l eone and the niesostom sliort, 

 |irisnioidal : cheilorhalidions fuse posteriorlv, lieinj; continuous 

 with six i)rostonialal ami mesolouiatal ruyae. Somi'tinies, in 

 addition, there are nunu'rous di'Mlicles at the junetions of jiro 

 anil uu sorlialiilions { Ildlii'liiniihildi mux) . On the basis of sto 

 matal eliaraeters we should, jierhaps, reeoRnize the sulifaniilv 

 Selaehinematinae ;is a valid Rroup of the Cyatholaimidae. 

 While tlu'v are undouliti'dl.v elosely related to elioanolainis 

 they ditTer in that cheilorhalidions are feebly developed and 

 the stiunatal eavity greatly redueed. The protorhabdions are 

 fused into three or two numdibles terminatinj; anteriorly in 

 several teeth. Of the diverse types, Si/no'ichii lUi Iniiicalu 

 seems the most Ki'nerali/ed sinee it has three eipml mandibles, 

 one dorsal and two subventral; eaeh of these mandibles is 

 distally bitid and bears several hook like oneliia. ('luininrhiis 

 bnlliosifs exemplifies a jiartial reduction of the dors.al mandibli' 

 while S< liifJiiiiniui firii.r (see cover. Sec. 1, I',art 1) reiiresents 

 complete reiluction in the dor.sal ni;indible and hy]iertropliy of 

 the subventrals into lateral jaws. 



The Tripyloididae seem misplaced in the Chromodoroidea, yet 

 their relationship with the eyatholaims on the liasis of otlier 

 characters makes their position here obligatory. In these forms 

 oheilorhabdions do not take the form of odontia. Instead 

 there are three large lips. Protorhabdions may exhibit numer- 

 ous .joints, the protostom being on the whole inverted, wide 

 conoidal in form (Triiti/Uiidix viitffaris. Batlii/laimus cahhi). 



DrniiKiildrdidta. Whenever the jirotorliabdions are distinctly 

 selerotized and the protostom not collapsed, desmodoroids 

 (Mrtochrdmailora ony.roiil<\i, Mdnopdsthia hexalaia, Dismoddra 

 sciihtriisis) exhibit all of the characteristics of the Chromadori- 

 dae, but quite often the stoma is completely atrophied, in 

 which case protorhabdions cannot be detected (Ccramonema 

 rfficiihitiim, Fig. 28). Though axial teeth are present in Spi- 

 rilla parasitifcra the protorhabdions are feebly developed and 

 cheilorhalidions not apparent. 



Pig, 62. 



Ceplialic regions in the Tripjioidea. A-C — Tripylidae. D-G — ironidne. 

 H — Mormnchidae. A — Prijtnuitolitinntit intermediuH. B — Triiiyla sp. 

 C — TrilnhttH Innpug, I) — Syrini/otaiinuH sniargiilu/t (upper) and ,S. 

 breviramliitiis (lower). E — IrniniH iyttdvus. F — Crypfonrhuft niidiiH. 

 G — Irnnclla prismutohiiniu. H — Mnnonrhufi gerlacht'l. I> — .Vftcr Cobb, 

 1928. J. Wa.sh. Acad. Sc, v. 1« (9). H — After de Man, 19U4, Expi-d. 

 Antarrt. Belg. Remainder original. 



I)< siiKinrolrroidia. So far as known, this group must be 

 characterized as liaving a rudimentary .iitonui witli no visible 

 stoniatorh.'ibdiuns. 



KnoI'I.i.na. Mi'mbers of the submclcr Knoplina do not 

 liavi' ;i protrusible onchiostyle and the eheilorhabilions do not 

 take the form of 12 odontia as in the Chromadorin.'i. In u 

 few instances they may form a transverse denticulate ridge. 

 In su(di instances tliey do not form .an armature of the lips 

 as sometimes occurs in tlu' Monhysterina. 



Tripi/ldidta (Fig. ()2). Herein are groui)ed four families, 

 separable on stom.atal cliaracters, the Ironidae, with a inucli 

 (•long;ite narrow stonui and heavily selerotized protorh.alxlions, 

 the .Maimidae with a rudimentary stonm, the Mononchidae with 

 a cap.acious stonui and very heavily selerotized stomatorhab- 

 dions, and the Tripylidae with weakly selerotized protorhab- 

 (lions. 



Mononchs usually have a subglobular stoma with a massive 

 dorsal jirostoniatal oneliium; the hatter may lie oppo.sed by a 

 variety of dental structures taking the form of tr;insverse d<'n- 

 ticulate ridges, longitudinal ventral ridges or small unchia 



Fin. 03. 



Cephalic regions in tlie Enoploidea. .\-F & L — Enoplidae. (J K & 

 M-Q — Om-holainiidae. A — Enoptus cominlitiijt. B — Eurystnwintt iniifri~ 

 cana. V — Enoploides amphioxi. D — Anticoma Jitoris. E — Phonod^r- 

 mopsia lonyisetue. F — Rkabdodemania minima. G — Oxy-ftomina alpha. 

 H — HulnUiimus caroUniensis. 1 — Kn^hetidiiim pauli, v. dentifulatunit 

 female. .1 — Knrhpiidium pauli, v. dentirulatum, male. K — liolhella 

 tenuidfns. L — ThoraroMtoma { PaeudocfUn) sp. M — Mctonrholaimus 

 printiurutt. N — Onrhotaimellus rlarndiscus. O — Aiwplostoma vii-iparum. 

 P — Poiydonfus iiinrinus. Q — P.ifudfipflat/onfnia eifyans. B, D, K, F, 

 H — After rhitwood, 1930, Tr. Amcr. Micr. Soc, v. f,a (2). C — After 

 Filipiev, 19IK, Trav. Lab. Zool. Stat, Biol. Sebnstopol, v. 2 (4). I, J — 

 After .Micolet/.kv. 19;)0, Vid. Medd. fra Dansk. .\atur. Foren.. v. 87. 

 K — After Cobb, 1920. Contrib. Sc. Nemat. 9. N — After de Man, 1890, 

 Mem. iSoc. Zool. France, v. 3. O — After de Man, 1907. Mem. Soc. 

 Zool. France, v. 20. I'-Q — After Kreis, 1934, Capita Zool., v. 4 (5). 

 Remainder original. 



71 



