FREE-LIVING NEMATODES 



461 



outnumber them; and the number of free-living individuals is 

 so great that they probably constitute one of the important 

 mechanical as well as biological factors in soil, and in the bot- 



Lateral field 

 , Pharyngeal bulb 



, Pharynx 



, Salivary gland 

 , Muscular Iiiyer 

 , CulJcula 



. Hair 



. Esophagus, 



. Cuticula 



. Nerve-ring 



, Duct ot ventral gland., 



. Esophagus. 



, Nerve ring 



,, Ridsc in ciilicula 



;. Esophagus 



- Stria of cuticula 



i. Sub-cuticuV 



I. "Wing of culirul; 



I. Cuticula. 

 . Cardiac bulb 

 1. Dorsiil field 

 I. Valvular apparatus 

 ,, Its radial nnusclei 

 ', Muscul ir layei 

 ;. Wall of Intestine 

 '. WinjT of cuticuh 

 I. Ovum fit to fertilize. 



, Blind end o^ary 

 Intestine ... 



. Yolk of egg. 



Nucleus of egg 

 , Shell of egg. 



Internal lateral field 

 . External lateral field 

 . Intestine 



. Copulatory muscle 

 , Wing of cuticula. 



Copulatory muscle 



Intestinal cell 



Accessory male organ..,., 



Ejaculatory duct 



Copulatory muscle 



Wing of cuticula . 



Constriction in spiculum 



Right-hand spicului 



Distal end spiculum 



Accessory piece 



Caudal gland 



Left wing of bursa 



Ibt caudal gland 

 2nd caudal gland 

 3rd caudal gland 



Muscul.ir wall 



Bight wmg of bursa 



Diagram of Nematode structure. 



Fig. 766. 

 Above, anterior end of female. 

 (After Cobb.) 



Cephalic eeta 



Labial papilla 

 Pharyngeal rib 

 Pharynx or throat 

 Phiirjngcal tooth 

 Pharyngeal bulb 



Salivary gland 

 Lateral or^an 

 Esophagus tube 

 Eye, with lens 



Excretory pore 



Ampulla 



Median bulb 



Is'i^rve-ring 



Ganglion celU 



Duct of ventral gland 



Duct of later.il gland 



A lateral gland 



Cardiac bulb 



Valvular apparatus 



Wing or ridge in skia 



Cardiac collum 



Cardia 



Stomach or intestine 



Tessellation of sams 



Cuticula 



Wall of intestine 



Ventral gland 



Stnation in cutjcula 



Ripe ovum 



Uterus 



Unripe ovum in ovary 



Spermatozoa 



Fertilised egg in uterus 



Blind end of ovary 



I'olk of egg 



Vaginal gland 



Vulva 



Vagina 



Vaginal gland 



Lateral field 



Seminal vesicle 



Wall of same 



Spermatozoa 



Copulatory muscle 



Aciessory male organ 



Ductus ejaculatoriua 



Three pre-anal papillae 



Copulatory muscle 

 , Proximal end spiculum 

 , Pylorus 



Anterior ribs of bursa 



Anal gland 

 . Anus 



Post-anal papillae 



Caudal gland 



Median ribs of bursa 

 . Bursa 



Posterior ribs of buraa 

 , Duct of caudal glands 

 , Terminus 



Below posterior end of male. 



toms of lakes and oceans. The aquatic nematode species exist 

 in enormous numbers, in both fresh and salt water, while the 

 number of individuals is past computation. The unavoidable con- 



