An additional process connects the posterior part of the 

 spicular ganglion to the ventrolateral nerve. In Ascaris 

 Voltzenlogel found many errors in Hesse's description 

 and diagrams of the male. Unfortunately no corrected 

 diagram was supplied. We have attempted to make one 

 on the basis of Voltzenlogel's description (Fig. 128 C) 

 ^ut it is necessarily liable to considerable error. Ac- 

 cording to the description each ano-rectal commissure 

 contains two lateral bipolar neurones and the medial 

 caudal nerve contains three dorso-cloacal neurones and 

 one postanal neurone after which this nerve divides, 

 sending a process to each lumbar ganglion. The two 

 pairs of bipolar subcloacal neurones originate from the 

 paired ventral nerve trunks and processes extend post- 

 criad where a third subcloacal neurone is found. No spicu- 

 lar ganglia have been described. Despite the great detail 



Ingenoid (Cell 20, Pig. D), (2) corynoid (Cell 18 Fig. A) 

 or (5) arfmoid (Cell 40, Fig. F). Small cells were classi- 

 fied as ((i) pi/)ifo>-m (Cells, 1, 2, 4, Fig. A) or (2") 

 roryiioid (Cell' 13, Fig. F). The Indirect cells (lb) con- 

 sist of large chonoid and small corynoid types. 



II Sensory cells. These are bipolar cells situated 

 either peripherically or centrally. They are of four gen- 

 eral types according to disposition: (1) Direct sensory 

 cells (Bipolar neurones of cephalic papillary nei-ves), (2) 

 Indirect sensory cells (Bipolar neurones of amphidial 

 nerves and genital papillae), (3) Collateral cells (Cells 

 essentially bipolar "out having one axone direct to nerve 

 ring and a second axone passing through a commissure 

 such as cell 39, innervating the deirid), (4) Unclassifiable 

 bipolar neurones of longitudinal nerves such as those 

 occurring in submedian and ventral somatic nerves (It 



i9 11pii;LHI16l1Bia]l22iaiz6tffll30l3glMI36l38IMH«mimmSOI52l5\imMIMIKiwl66'6ai70 



Fig. 133. 



Diagrams of parts of nerve ring of Ascaris liimbricmdes. Dorsal 

 part of nerve ring on readers' left, ventral part on readers' right. 



See also fig. 

 V. 92 (2). 



130. After Goldschmidt, 1909. Ztschr. Wiss. Zool., 



of Martini's work on Oxyiiris equi we are unable to fol- 

 low his description without diagrams. Looss is more 

 intelligible and kindly supplies the needed diagrams but 

 is not too exact. His findings in the female of Ancylos- 

 toma correspond with ours on SpironoiDxi except that 

 he found four neurones of the medial caudal nerve an- 

 terior to the anus. Two processes extend posteriad from 

 the ends of the ventral nerve to the anterior anal lip. 

 In the male the system consists of two commissures, one 

 of which connects with the suprarectal ganglion, dorsal 

 to the spi;ules, while the other connects with the sub- 

 rectal ganglion, ventral to the spicules; the two ganglia 

 are connected. The commissure connected with the 

 suprarectal ganglion joins on each side with a subcloacal 

 ganglion from which a group of fibers passes posteriorly 

 to the dorsal side of the guoernaculum. There is ob- 

 viously a distinct similarity in findings and differences 

 between the conditions in Ascctris, Spironoio-a and Ancy- 

 lostoma may be superficial and not important when an 

 adequate amount of information for critical analysis is 

 available. 



Finer Structure of Nervous System 



Work on the finer structure of the nervous system 

 has been confined to Ascaris honbricoidcs. Goldschmidt 

 (1908) classified the nerve cells of this species as follows: 

 I. Ganglion cells. Central cells (i. e. with one or rarely 

 two processes to nerve ring) either (a) l.irect or (b) 

 Indirect (pass through a commissure before reaching 

 nerve ring) and II. Sensory cells. 



I. Central cells. The direct cells (la) were subdivided 

 according to size and shape; large cells (Fig. 130) termed 

 (1) chonoid, (Cell 23 Fig. V); (2) corynoid, (Cells 

 7-12, Fig. A); or (3) amplwroid, bipolar (Cells 19-20, 

 Fig. B). Medium sized cells were classified as (4) 



seems dubious that these cells should be classified as 

 sensory without knowledge of their ultimate destinations). 



Supporting tissue. The supporting and ensheathing 

 substance of the nervous system is called glia. Cells 

 which form this connective tissue are of several types, 

 some being very closely integrated into the general 

 nervous system, the glia cells, others being less intimately 

 associated. These latter include the escort cells (Geleit- 

 zellen) and the clavate cells (Kolbenzellen). 



According to Goldschmidt (1910) the chief mass of 

 glia which surrounds the nei^ve ring in Ascaris is two 

 to three times as large as the nerve ring itself and con- 

 tains nests of three to four small nuclei (Fig. 130 W). 

 Some of the tissue and nuclei extend into the lateral 

 chords. Special glia cells of the cephalic papillary 

 nerves have already been described. 



Each large ganglion cell has a specific glia hull sur- 

 rounding it. According to Goldschmidt this material is 

 often poorly fixed but in satisfactory preparations it may 

 be seen that glia fibrils actually enter the ganglion cell 

 (Fig. 130 V) thus causing the appearance characterized 

 as "radially striated" ganglion cells. All nerve fibers 

 have one or more neurofibrils and these are in direct 

 continuity with the glia fibrils which may form a basket- 

 work around the nucleus. The protoplasm of ganglion 

 cells is essentially alveolar and the web conforms to the 

 radial fibril structure. Tigroid substance (Nissl bodies, 

 chromophil substance) is sometimes fine and generally 

 distributed throughout the cell while at other times it is 

 icoarse and localized (Fig. 130 R-U). 



Muscle iNNBaiVATiON. Due to the efforts of Schneider 

 (1866) and later workers the nemic "innervation pro- 

 cesses", by which somatic muscles are connected with 

 longitudinal nerves, have received a great deal of pub- 

 licity and it is widely accepted that nemas differ from 



171 



