limy 111' li'iiiu'ii li, t< rdCiilDiix wliilc f<iniis in wliirli tlic ullrrna 

 tive is triio may lie tcrnu'd hiininfi/ldiis. 



Ceu, Size. — The intestinal lumen may be rdimileil, sub 

 |)oly(jonal or quite irreKular. A lumen of snidiitli ei>nt<iur 

 occurs in oligoeytous forms, thouttli even in such forms it may 

 become irrcKular due to folds or ru^ai', involving the entire 

 epithelial wall. A sub|iolynonal binien is characti'ristic of 

 polycytous forms wherein each individual cell tends to cause 

 a concavity in the outline of the lumen. Sonu'tinu's in pnhicy- 

 tons forms, but nuire commonly in myriocytnus forms, there are 

 definite projections of cells into the hnneii, such cells being 

 taller than their neighbors; these groups of cells form villi or 

 plicae (Fig. lO.S E, F, I). This inequality in the height of 

 cells in a given cross section may be termed anixncjiUi while 

 the reverse would be isncytii. 



NrcLEAR Nl'MBER. — As a rule intestinal cells in nematodes 

 are uninucleate but exceptions to this rule are becoming more 

 and more numerous with critical observation. The causes of 

 polyiuicleation are not known; one can only inter]iret from 

 scattered observations. Normal "Ciigantism" of oligocytous 

 forms appears as one of the factors. Treniondo\is increase in 

 cell size siudi as occurs in Strotif/j/lus rqiiiniis, where one finds 

 single intestinal cells 4 mm long by .'>(H1 M wide, apparently 

 increase the requirements of nuclear material to such an extent 

 that a uninucleate cell nuiy be at a disadvantage. Given an 

 equivalent amount of nucleoplasm many nuclei provide for 

 more nuclear surface and a closer association of cytoplasm 

 with nucleoplasm than could be obtained with a single nucleus. 

 One might say that nemas inherently unable to cojitinue cell 

 cleavage compensate for this by undergoing nuclear division 

 when natural forces no longer limit their size. Polynucleation 

 is known to occur only in iiarasites. When characteristic of 

 the entire intestine it is usually present in an entire natural 

 group, but the exceptional sporadic cases (CnatJinstoma, PhUn- 

 vietra) are not explainable at jiresent. 



Increase in cell size in tylenchids can not be the cause of 

 polynucleation since these forms are no longer than rhabditids. 

 Quite obviously an insufficient amount of information has thus 

 far been gathered to permit far reaching general conclusions. 



Classifying nematodes according to the number of cells of 

 the intestine, number of nuclei, specialization or lack of special- 

 ization, and equality or inequality of cells provides an in- 

 teresting survey of the Nematoda. Examples of the known 

 types are given in the accomiianying table. 



TABLE 1 



Cell Nuclear Cell Cell 



No. No. Size niaraeter 



Oenus (1) (2) (,S) (4) 



Rhabditis + + + + 



Ditylenchus -.... + — + + 



Chondronema — + + -f 



Strongylus - + — -\- + 



Rhabdias — + + -j- 



Hystrignathus — + + + 



Spironoura = + — + 



.\scaris = + — + 



Phy.saloptera = + — -|- 



Tanqua ^ + — -|- 



Onathostoma = — + + 



I'hilometra ^ — — + 



Prionchulus — + + + 



Metoncholaimus — -(- + — 



Monhystera + + -|- 4" 



.\nonchus + + + + 



Plectus - — 4- 4- + 



Halanonchus - — + + + 



Dorylaimopsis — + + — 



Svnonchiella - — -|- -f- — 



Tripyla ± + + + 



Leptosomatum — + + — 



Enoplus - - — + + + 



Ironus - -— — + + — 



Dorylaimus — + + + 



Lcptonchus ? + + + + 



.\gameris - — — + + 



Trichuris ^ + — + 



Dioctophvma = + — + 



(1) (2) (.3) (4) 



-|- is oligoey- -|- is uninucle- + is isocytous + is honiocy- 



tons ate — is anisocy- tous 



— is polycy- — is polynu- tous — is heterocy- 



tous cleate tous 

 := is myriocy- 



tous 



C. CELL INCLUSIONS 



Under this hi'ading ;ire included all substiinces which are 

 not 11 part of the active cytojilasni whether organic or inor 

 ganic, food reserves or waste products. Numerous types of 

 stored food and waste products have been (di.served and in 

 addition there is a residuum of luui-classilied material termed 

 sphaeroids or granules. Food reserves are known to include 

 glycogen, rhabditin, fats, and protein. Waste jiroducts are 

 for the most part not classified chemically. 



(1) RESERVE KOOD MATERI.M,S 



(Hi/riif/rn. This substance, when present, is in a liquid or 

 seniiliquiil state, since it is water soluble. In fresh material 

 it may be icb'utitied through its coloraticpii with iodine iiotas- 

 siumioilide solution or the Rest's carmine technic as described 

 by Lee (l!t2.S). (iiovannola (lit.^fi) has recently emi)loyed the 

 new Hauer (li(33) technic for staining glycogen in the intes- 

 tine of iireiiarasitic larval Anctiloxlnma faninum, Necalor 

 amrricaniis, and Xippnstroiifiiiliix miins. Tt is always best to 

 use a saliva enzyme control, because that which is removed by 

 .saliva is presumptively carbidiydrate in nature. Busch {ISIO.'i), 

 von Kemnitz (]il]2) and Quack (191.3) found glycogen to he 

 the chief stored food in the intestinal epithelium of adult 

 Asraris and Striytu/iihiii. diovannola rejiorted glycogen to be 

 the chief f<iod reserve in the larvae of parasitic nematodes 

 jireceding an<l during rapid growth. 



Hhahdiliii. This occurs as birefringent sphaerocrystals de- 

 scribed by Maupas (1900), Cobb (1914) and .lacobs and Chit- 

 wood (l!t,'?7) from the intestinal epithelium of Rhabililis spp. 

 The sphaerocrystals are grey in color, bright sjiots in dark 

 field illumination and bright spots with a central cross when 

 observed between crossed Nichols of a polariscope (Figs. 

 lOOA-B & 101). They are slowly soluble in cold water, more 

 rapidly on boiling; they are moderately soluble in .'i% for- 

 malin, and in lOTr acetic acid; rapidly soluble in dilute and 

 concentrated hydrochloric, sulfuric, and nitric acids, in ")0% 

 formalin, and in sodium and ammonium hydroxides; they are 

 insoluble in alcohol, glycerin, and xyol. When the intes- 

 tines of specimens are mashed out under a cover slip and ex- 

 posed to saliva or diastase at 37..5°C., these birefringents dis- 

 appear from the intestine in one-half to one hour while ap- 

 proximately twice this time is necessary in water and in in- 

 activated saliva controls. Iodine-potassium iodide has no ef- 

 fect. Presumably rhabditin is a carbohydrate but attemjits to 

 starve specimens and reduce the number of crystals were with- 

 out effect. They disappear, however, when the larvae enter 

 the encysted third stage (become "dauer" larvae). 



Similar sphaerocrystals were described from the intestine of 

 Tlirrixliis xetn.iiis by the writers (1938). 



Fats and Fatti/ Aciilx. These substances are present as 

 colorless globules imiiarting a grey opaque color to the or- 

 ganism. In dark field illumination they appear as bright 

 circles, and between crossed Nichols they are not visible. Such 

 material may be identified through its coloration with Sudan 

 III, Scharlach R, Nile blue sulphate, osmic acid, and Fleni- 

 ming's Strong fixative. It is not dissolved by saliva, water, 

 or hydrochloric acid and gives neither .xanthoproteic nor nin 

 hydrin reactions. It is, of course, soluble in alcohol, xylol 

 and ether. Standard histological technic results in the ap- 

 pearance of large empty spaces or vacuoles wherever fats 

 were present in the cell. Semipermanent mounts of small 

 nematodes may be obtained by alcohol fixation, and evapora- 

 tion to glycerin in Scharlach R or Nile blue sulphate accord- 

 ing to the procedure of fioodey (1930). Pleasing temporary 

 mounts can >)e made by placing living specimens in alcoholic 

 solutions of Scharlach R. The most exact method is to cut 

 the specimen, let the intestine flow out of the body and 

 stain with Scharlach R, osmic acid or Flemming's fixative. If 

 desirable they may be counterstained with haematoxylin. Per- 

 manent prejiarations may be made by sectioning osmicated 

 specimens. 



Von Kemnitz (1912) and Quack (1913) found fat globules 

 in small amount in the intestine of adult A.tcari.i and Strangy- 

 lux. Giovannola (193(i) concluded that fat is the primary food 

 reserve in larval iiarasitic nematodes in stages preceding a pe- 

 riod of fasting. He further states that the quantity of fat 

 globules is an index to the "physiological age" of prcparasitic 

 strongyloid larvae. More critical investigaticms along such 

 lines would seem promising. Goodey (1930) identified fat 

 globules in the intestine of representatives of the Tylenchidae, 

 Rliabilifidae, Diplogasteridae, Ceiihalobidae, Plectidae, and 

 Momuichidae. The writers have identified fat as the chief 

 form of stored food in Cephalnbrlliix and BlaUicola (Thelas- 

 toinatidae), Chondronema (Allantonemafidae), Spironnvra 



103 



