previously noted that sphaerocrystals are normally eliminated 

 in the faeces. 



Spirurida (Fig. 103). For the order Spirurida there is a 

 surprising dearth of recorded knowledge concerning the in- 

 testine. Jagerskiold (1893, lSi)4), Magath (1919), Hether- 

 ington (1923) and Tornquist (1931) seem to have been the 

 only authors who gave the intestine consideration. It is pe- 

 culiar that in this group there appear to be as many instances 

 of marked dissimilarity of the intestine in closely related forms 

 as there are instances of similarity. All of the members of 

 this order appear to be myriocytous with the possible excep- 

 tions of Gnathoxtoma and Philometra : the latter have rela- 

 tively few, large, polynucleate cells (Fig. 103U & W). In- 

 soluble sphaerocry.stals are present in Philometra, Dracunculus, 

 Microplciira, CamallanKs, Gnathostama, and Ttinqiin, while they 

 are absent in Ascarojihis (Metaironeina) , Cticidlanus, Pliysalop- 

 tera and Eictularia. Basophilic globules, probably of a pro- 

 tein nature, are present in Rictiilaria. Most of the represen- 

 tatives of this group have very tall, narrow intestinal cells 

 and are anisocytous because the epithelium exhibits either 

 longitudinal ridges and valleys or villi. However, three forms 

 are conspicuous exceptions to this rule, namely, Camallanus, 

 A.icarophis and Gnalhostoma. Diversity in height of cells and 

 character of the bacillary layer and basal lamella are also 

 conspicuous features of the group. 



Chromadorida (Fig. 104). In the Chromadorida the only 

 observations regarding the intestine have been of an incidental 

 nature. We have records such as those of de Man (1884) in 

 which species of the genus Monhystera are differentiated on 

 the basis of their having a black or grey intestine and "two 

 cell rows" or more than two cell rows. The rich red-brown 

 to black pigmentation of the intestine of Siplionolaimus was 

 recorded by zur Strassen (1904). The number of cells in an 

 intestinal circumference was mentioned by Cobb (1920) in 

 many forms of this group. Zur Strassen (1904) and Schepo- 

 tieff (1908) were the only previous workers to study sections 

 of forms of this order. 



Members of the family Plectidae have relatively few intes- 

 tinal cells, 120 to 930, the form with the smallest number, 

 Anonchus, being oligocytous while the remaining forms stud- 

 ied, Plectus, Chronogasier, and Wilsonema are polycytous. 

 Anonclius and Chronogasier have only four cells in a circum- 

 ference, a very low bacillary layer, flat lumen, and large eosino- 

 philic granules. Wilsonema has up to eight cells in a circum- 

 ference, a lobed lumen, high bacillary layer and no granules 

 and Plectus has up to 12 cells, a rounded lumen, high bacillary 

 layer and basophilic globules ( "? protein). 



In the family Camaeolaimidae, Aphanolaimiis has around 

 100 cells (oligocytous), a flat lumen, a high bacillary layer, 

 four cells in a circumference and basophilic globules like 

 Plectus while Camacolnimns has around 2ri6 cells (low poly- 

 cytous), a rounded lumen, low bacillary layer, six cells in a 

 circumference and reddish-brown nnn staining granules. 



Sabatieria and Dorylaimopsis, of the Comesomatidae, are 

 polycytous, having 2^G to 500 intestinal cells, six to eight in a 

 circumference, tliey also have a flattened lumen, a low bacil- 

 lary layer and large basophilic globules. They differ from 

 one another in that Sabatieria is apparently homocytous while 

 Dorylaimopsis is heterocytous having scattered cells contain- 

 ing large acidophilic masses (Fig. 104G). 



In the Axonolaimidae the intestine is approximately as in 

 the Comesomatidae, there being around 256 cells, six in cir- 

 cumference, a rounded to flat lumen and reddish-brown, non- 

 staining, sphaeroids. Ijike Sabatieria, Axonolaimvs appears 

 to be homocytous. 



In the Monhj'steridae there are two quite different types 

 of intestine. In the first, exemplified by Mojiliystera and 

 Theristus, the lumen is niultiradiate (Fig. 104C) tlioiigh there 

 are, respectively, 60 and 120 cells, two and four in circumfer- 

 ence; the l)acillary layer is low and compact and the intestinal 

 inclusions are brownish or grey and basophilic. In the second, 

 exemplified by Ualanoncliiis, there are about 566 cells, six to 

 16 in a circumference; the bacillary layer is relatively higher, 

 less compact, the lumen irregular, and the sphaeroids are 

 brownish and non staining. 



Linhomoeids commonly have few intestinal cells in a cir- 

 cumference, usually two in the mid-regio7i of the intestine, 

 but the total number of cells varies considerably. Tripylium 

 has 26 cells while Terschellingia and Desmolaimiis exhibit 

 around 128; the lumen is flat to rounded, the bacillary layer 

 low, compact (not resolvable in Tripylium but so in the other 

 two exam|)les) ; the colorless globules in Tri|)ylium are soluble 

 in alcohol (therefore presumably fatty), while in Terschellingia 

 and Desmolaimus the cell inclusions are sphaeroids, slightly 

 brownisli, and insolubU". 



ITnlike other inonhysterids and linhomrn'ids, tlu' sijilK»n(ilaini 



intestine is deep red to black in color, the pigmentation being 

 due to refractive, insoluble sphaeroids. Zur Strassen (1904) 

 found the intestine of SipJionolaimus weismanni to consist of 

 22 cells in circumference and to be composed of a total of 

 6,000 cells (estimation from statements in description) ; its 

 lumen is rounded, the bacillary layer unusually high. 



Members of the Chromadoridae, Microlaimidae and Des- 

 modoridae fall within the lower limits of polycyty, varying 

 within the narrow range of 128 to 256 cells. Seemingly all 

 have a four cell circumference in the mid-region though 

 there may be six to eight in a circumference in the ventricular 

 region. Members of these families have a very low bacillary 

 layer and a rounded to subpolygonal lumen; a moderate num- 

 ber of somewhat basophilic sphaeroids is usually present and 

 in addition, from the coarse vacuolate appearance of the cyto- 

 plasm, one might suspect a considerable amount of fatty 

 substances. These three families appear to be homocytous and 

 isocytous. 



Members of the Cyatholaimidae, on the contrary, are more 

 distinctly polycytous, varying in cell number from around 

 256 to 1,000 with from three to 12 cells in circumference; they 

 appear to be uniformly heterocytous. In HaUchoanolaimus 

 the normal cells contain brown sphaeroids (often appearing 

 in section as basophilic shells) while the scattered heterocytes 

 are devoid of these bodies but contain instead, large vacuoles 

 packed with baso|)hilic globules. In Synonchiella the normal 

 cells are vacuolate, without sphaeroids, and the heterocytes are 

 dense, filled with basophilic globules (Fig. 104A). The simi- 

 larity of the intestine of Haliclioanolaiinus to that of Dory- 

 laimopsis is very striking. 



Schepotieff (1908) described the intestine of Desmoscolcx 

 as consisting of few cells and as containing very large brown- 

 ish globules which were insoluble in alcohol-xylol. 



Enoplida (Figs. 105-107). The order Enoplida, containing 

 both simple and complex free-living forms, as well as diverse 

 types of parasites, shows extreme variation in the form of 

 tlie intestine. 



Within the Tripyloidea, Stefanski (1916) studied the cell 

 inclusions of Ironus and Cobb (1917, 1918) described the 

 intestine of Ironus and Mononchus. Ironus is polycytous and 

 heterocytous (Fig. 106), the number of heterocytes apparently 

 varying with the species. The ordinary cells contain yellowish 

 non-staining sphaeroids which appear as shells with irregular 

 contents in formalin preserved material. These sphaeroids are 

 sometimes eliminated through the anus (Fig. 105O). Tripyla 

 (Fig. 105A-C) is homocytous and barely polycytous, having 

 136 to 150 intestinal cells, a low bacillary layer, acidophilic 

 granules and scattered polygonal crystals. Prionchulus is like- 

 wise polycytous and homocytous (Fig. 105D-E); the species 

 differ in having from 170 to "00 intestinal cells; anteriorly 

 the cells in a circumference are more numerous, higher, and 

 have a much more pronounced bacillary la^-er than in the mid 

 region but no definite ventriculus is present. Like Ironus, 

 Prionchulus has acidophilic granules but crystals are absent. 



In the Enoploidea Tiirk (1903), Jagerskiold (1901), and de 

 Man (1904) studied the intestine of Thoraensfoma and CvH- 

 colaimus and Rauther (1907) that of Enoplus; Cobb (1922, 

 1924a) investigated the intestine of Eurystomina and Ajiti- 

 coma and Chitwood (1931) that of Metoncholaimus. So far 

 as known, all members of this group are markedly polycytous, 

 isocytous, and have uninucleate cells. With the exception of 

 Enoplus they are all heterocytous and even in this form cells 

 are occasionally found which differ from their neighbors in 

 the presence of large acidophilic bodies. Tiirk found the homo- 

 cytes of Thoracostoma to contain greenish-brown granules. 

 Specimens kept in clean white sand had a clear intestine free 

 from such inclusions. He judged these inclusions to be re- 

 sorption vacuoles of plant food. Occasional heterocytes he 

 interpreted as fat cells (Fig. 105M-N). A bacillary layer ap 

 pears to be totally absent in Metoncholaimus, Thoracostoma 

 anil Cylicolaimus. This layer is represented merely by a 

 peripheral condensation in Eurystomina (Fig. 105G-H) and 

 Leptosomatum (Fig. 105L) while it is nuxlerately high and 

 distinct in Enoplus and very high, especially in the ventricular 

 region, of Phanodermopsis. The ordinary cells (homocytes) 

 of Phanodermopsis contain yellowish non staining sphaeroid 

 shells (J'ig. 1051) while the corresponding cells of Lepto- 

 somatum have a conspicuously vacuolate plasma (? fat vac- 

 uoles) and a few baso])hilic globules; the homocytes of the 

 remaining forms contain acidoidiilic granules. Heterocytes 

 in Eurystomina and Phanodermopsis' are filled with basophilic 

 globules while the heterocytes of Leptosomatum include a large 

 amorphous acidophilic vacuole and those of Metoncholaimus 

 may either be basophilic with a large vacuole or ciintain scat- 

 tered large yellowish non staining sphaeroids (Fig. 105F). 

 Chitwood :in.i Cliitwood (\'XM') identified fats .■ind ferrous 



lOS 



