indiciitod liv tlio tloi-snlly (itiHfiuc stylrt api'iturc. It is of fur 

 tlu'i- iiitiTOst to iioto tli:it in slU'li foriiis as Ddiiiliiiniiix anil 

 AftiniiUiiiiiiix the stylot is fornio(i as a cyliniicr in one of tin' 

 snlivcntral soi'tois of tlio I'sopliaRoal wall; a new stylot moves 

 up to its final position at eaeli molt; while forminR, the onehial 

 cylinder lias an ojien eraek on the side awa;/ friim the lumen. 

 Most ilorylainiids Iiave little ovidenee of the original proto- 

 rhal>ilions, tliose being best preserved in Xi/ffolaimus and 

 ActiiKihiimun. The latter is a most unusual member of the 

 group having a radially striated eheilorhabdion and four mas- 

 sive, onehium like, stylet guides in addition to heavily selero- 

 tized Jiru and inesorliabilidiis and sli/li t fiuulinii riiifl. Since 

 the latter structure is absent in sucli forms as Xi/j/dldiiinin we 

 may iiresume it to be the modified telorhabdions or metarliab- 

 dions. However, its homology has not been determine<l. Tn 

 dorylaimids the stylet may become tremendously elongated 

 (Triclimlonis obtii.tus, Lcpldiirhus flranittitsiis) and in addition 

 it may he terminated in three flanges (Tiilincliolaimiis acqua- 

 lis) or knobs (Xiphintma amcriranvm). In the latter in 

 stance we have a case of total convergence witli tylenehoida in 

 gross stylet morphology. The guiding ring and oblique stylet 

 aperture provides us with a elue to its dorylaim origin. Stylets 

 with fl.'inges or knobs usually show a .joint (Xijiliinrma) ; this 

 .joint indicates the extent of the true st.vlet. The anterior part 

 is the only part formeil in the esophageal wall; the posterior 

 part with flanges or knoljs, is fornieil in situ and may be con- 

 sidered a differentiated continuation of the esophageal lining. 



The developmental origin and significance of the stylet in 

 Diphthirophora comminiis and D. perplcrans have not been 

 solved as yet. These forms have a short massive stylet with a 

 comi)licated dorsal arch at its anterior end and three large 

 knobs at its posterior end. 



Mrrmithoidca (Fig. 04). The first stage larva of such mer- 

 mithoids as A(/a»iir»ii.<i ilt'cniidatii, Mennis siibiiii/rcxceiis and 

 nrjiinnrmis albicans have an onchiostyl quite similar to that 

 of Voiiilaimiis and the stoma is completely atrophied. In the 

 adult, as a rule, one can distinguish no .semblance of stylet or 

 stoma, and the esophageal lining extends to the oral opening, 

 hut in a few forms a very minute stylet rudiment has been 

 described. 



Trichuroidia (Fig. 64). Fiilleborn (1923) showed that the 

 first stage larvae of Trichiiris trichiura, Trichinclla spiralin 

 and Trichnsomoidex crax.iicaiala all have distinct stylets. It 

 is customarj- to assume that all trace of stylet disappears in 

 the adult stage but Li (1933) has found a distinct func- 

 tional stylet in adult Triclinris triclitira and the writers have 

 seen one in adult Trichtiris riilpix. Such stylets are very 

 difficult to observe in fixed material and should be studied intra 

 vitam, possibly with the addition of such stains as crystal 

 violet or iodine — 1 per cent sulphuric acid. Of all trichuroid 

 stages observed by the writers, the neotenic male of Triclioso- 

 mnidi's crassicaiida has a stylet most easily studied. 



DlO('TOPHYM.\TlN.\. In adult dioctophymatins the stoma 

 is entirely rudimentary; no distinct cavity nor stomatorhab 

 dions can be observed and the esophagus extends to the oral 

 opening. Orifices of three large esophageal glands at the oral 

 opening seem to indicate definite affinities with enoploids. How- 

 ever, Lukasiak (1930) described a protrusible st.vlet in the 

 first stage larva of Dioctuphi/ma renale. If this observation is 

 verified it will lenil additional weight to the trichuroid-diocto- 

 phymatoid relationshiii. Such a relationship was first pro- 

 posed liy Rauthcr (1918) on the basis of gonads and is sup- 

 ported by the similarity of eggs, spicule and protractor muscles 

 of the spicule. 



Bibliography 



Bastian, H. C. 1X6.1. — Monograph on the Anguillulidae, or 

 free nematoids, marine, land, and fresh w-ater; with de- 

 scriptions of 100 new sjjecies. Tr. Ijinn. Soc. Lond., v. 25 

 (2): 73-l,S4, pis. 9-13, fig.s. 1-24S. 



1S66. — On the anatomy and physiology of the nema- 

 toids, parasitic and free ; with ob.servations on their zoo- 

 logical position and affinities to the echinoderms. Phil. 

 Tr., Lond., v. l.">6: r)4.')-63S, pis. 22-28. 

 B.wus, H. A. 1921. — A new genus of nematodes parasitic in 

 elephants. Panisit. v. 13 (1): r>7-66, figs. 1-7. 



1921. — On the classification of the Ascaridae. U. The 

 polydelphis group; with some account of other a.scarids 

 parasitic in snakes. Parasit. v. 12 (4) : 411-426, figs. 1-7. 



1923. — Idem. III. .\ revision of the genus Dujardinia 

 Oedoelst, with a dcscrijition of a new genus of Anisakinae. 

 Ibid., V. ITi (3): 223-232, figs. 1-8. 



1930. — Some Jleterakidae and Oxyuridae [Nematoda] 

 from Queensland. Ann. & Mag. Xat. Hist. s. 10, v. .t: 

 .3.".4-306. figs. 1-10. 



M.wi.is, II. A. and DAniNKV, K. I9J2.— Keport on the i>ara- 

 sitic ni'nuitodes in the colh'ction of the Zoological .Survey 

 of India. Mem. Ind. .Mus. v. 7 (4): 264 347, figs. l-7."i. 



1926. — A .synopsis of the families and genera of 

 Ncniatoda. London. Urit. Museum. 277 pp. 

 Hl'TsruM, O. 1873. — Beitriige zur Kenntniss iler freiiebenden 

 Nematoden. Nova Acta Deutsch. Akad. Xatnrf, v. 3(i (.',): 

 1144; |)ls. 17 27, figs. 1 ()9. 

 Ciin'wooi), H. (i. 1932a. — The basic plan of the nervous system 

 of nematodes. J. Parasit., v. 19 (2): 167. 



19321). — A synopsis of the nematodes parasitic in in- 

 -sects of the familv HIattiil:ic. Ztsclir. I'ar.-isit. v. ."i (1): 

 14-50; figs. 1 59. ' 

 Chitwood. R. (i. and CinTWOOii. .\I. B. 1933. — The characters 

 of a protonematoile. .1. P;ira«it., v. 20 (2): 130. 



1934. — Nematodes parasitic in Philippine cockroaches. 

 Philipp. J. Sc. V. 52 (4): 381 392; pis. 13, figs. 119. 

 CmrwooD, H. «. and Wkhr, E. K. 1932.- The value of head 

 characters in nematode taxonomv and rel.-itionsliips. ,J. 

 Parasit., v. 19 (2) : 167-168. 



1934. — The value of cephalic structures as characters 

 in nematode classification, with special reference to tlie 

 Spiruroidca. Ztsclir. I'aiasit.. v. 7 (3): 273-335, figs. 1 20, 

 1 plate. 

 (IllKI.STlE, .J. B. 1924. — [The embryology of .Ic/diiiriniix dfcaii- 

 data.] ,1. Parasit., v. 11: 111-112,'fig. 1. 



1!I31. — Some nemic parasites ((Jxyuridae) of Coleop- 

 terous larvae. J. Agric. Res., v. 42 (8) ! 463-482; figs. 114. 



1936. — Life history of Ai/amrniiis drraiidatn, a nema- 

 tode parasite of grasshopiiers and other insects. .1. .\grie. 

 Res., v. 52 (3): 161198; figs. 1-20. 

 Cobb, N. A. 1898. — Extract from Ms. report on the parasites 

 of stock. Misc. Publ. No. 215, Dept. Agric, N. S. Wales, 

 62 pp., 129 figs. 



1913. — [New terms for the lateral organs anil ventral 

 gland. 1 Science, N. S., v. 37 (952): 498. 



1913. — New nematode genera found inhabiting fresh 

 water and non-brackish soils. .1. Wash. .\cad. Sc, v. 3 

 (10): 432-444, 1 pi. attached. 



1915. — Sf'Iachinema, a new nematode genus with re- 

 markable mandibles. Contrib. Sc. Neniat. (4): 113-116. 



1917. — Notes on nemas. Contrib. Sc Nemat. (5): 

 117-128. 



1917. — The Mononchs i Manoncliutt Bastian, 1866). A 

 genus of free-living predatorv nematodes. Contrib. Sc. 

 Nemat. (6): 129-184, figs. l-Vo. Also in Soil Sc, v. 3 

 (g) : 431-486. 



1918. — Estimating the nema population of the soil, 

 r. S. D. A., B. P. I. Agric. Technology Circ. No. 1, 48 

 pp., 43 figs. 



1919. — The orders and classes of nenias. Contrib. Sc. 

 Nemat. (8): 214-216. 



1920. — One hundred new nemas. Contrib. Sc. Neniat. 

 (9) : 217-343, figs. 1-118. 



1920. — Microtechnique. Suggestions for methods and 

 apparatus. Tr. Amer. Micr. Soc, v. 39 (4): 231-242, 

 figs. 1-6. 



1922. — A new sjiecies of Xiiflolaimiis, an outstanding 

 genus of the Dorvlaimidae. .1. Wash. Acail. .Sc, v. 12 

 (18): 416-421; figs. 1-2. 



1923. — The pharynx and :ilimentary canal of the hook- 

 worm larva-.V (cafor (imcri<'(i«».s\ .1. Agric. Res., v. 25 

 (8) : 359-361, plate 1. Ibid., (shortened). .1. Parasit., v. 9: 

 244-245, fig, 5. 



1923. — Amphids in ]iai;isitic nemas. .1. Parasit., v. 

 9: 244. 



1923. — Interesting features in the anatomy of nemas. 

 J. Parasit., v 9: 242 243 ; figs. 3-4. 



1923. — Notes on Paruti/Ienchns. a genus of nemas. 

 Contrib. Sc Nemat. (14):' 367 370; 1 fig. Also in .1. 

 Wash. Acad. Sc, v. 13 (12): 254-257; 1 fig. 



1923. — An emendation of Eoplolaimus Daday, 1905, 

 nee auctores. J. Wash. Acad. Sc, v. 13 (10): 211-214; 

 figs. 1-4. Contrib. Sc Nemat. (13): 363-366; figs. 1-4. 



1924. — The amphids of Caconemn (nom. nov.) and 

 of other nemas. J. Parasit., v. 11: 118 119; fig. N. 



1924. — Food of rhabilites and their relatives with de- 

 scriptions of two new rhabdites and a new rhabditoid 

 genus. .1. Parasit., v. 11: 110-117, figs. K and M. 



1924. — Notes on the amphids of nemas. J. Parasit., 

 V. 11: 110-111; figs. F H. 



1924. — Amphids on oxyurids. .1. I'arasit., v. 11: 108. 



1925. — Amphidial structures in nemas. J. Parasit., 

 V. 11: 222-223. 



73 



