NEMATODE GENUS PHYSALOPTERA. 1005 



Two cervical papillte ai^e present. These are situated laterally 

 a short distance behind the cephalic extremity. They are small 

 and spike-like, and stand out at right angles to the body. 



The excretory pore is ventral in position, and is situated a 

 very short distance posterior to the cervical papillae. It gives 

 exit to a thin duct, which at first passes obliquely inwards and 

 forwards and then bends backvv^ards to join an oval, elongate, 

 and unicellular gland pressed against the ventral surface of the 

 oesophagus. 



Two lips are present. These are lateral in position, and have 

 their inner faces flattened and their outer somewhat convex ; in 

 lateral view they may be semicircular, dome-shaped, or more or 

 less triangular in outline. They are always simple and their 

 pulp is never subdivided. Each lip carries a variable number of 

 teeth on its anterior and inner border ; these consist typically of : 

 (1) an outer median tooth, generally triangular in shape and of 

 variable size ; (2) an inner median tooth immediately intei"nal to 

 the outer median : it may be larger, smaller, or of the same size 

 as the outer tooth, and its tip ma}' be either simple and pointed 

 or broadened out and tripartite; (3) two inner lateral teeth, 

 one situated in each, of the submedian fields of each lip on its 

 inner surface : they are smaller than the outer tooth and are 

 always split ; (4) a series of small denticles a,rranged in a linear 

 series on the inner surface of the lip, dorsad and ventrad of the 

 median teeth. The external median tooth is ahvays present, but 

 any or all of the other teeth can be absent. Two papillse axe 

 present on the external surface of each lip ; these are situated 

 one in each submedian field towards the angles of the lips ; they 

 are generally dome-shaped. A number of observers mention the 

 presence of an additional external papilla in the mid-line of the 

 lip. I have not detected any such papillse in anj^ of the specimens 

 studied, and I am consequently led to the conclusion that a small 

 shoulder-like bulging, somtimes present on the outer surface of 

 the lip, has been mistaken for a papilla. 



The oesophagus is a straight and cylindrical organ, increasing 

 slightly in thickness towards its posterior extremity. It is 

 always divisible into two parts, namely, a short, transparent, and 

 slightly thinner anterior muscular portion showing transverse 

 rauscular striations, and a posterior glandular portion which is 

 thicker, oqaque, and granular. Its lumen is lined with chitin 

 and is triradiate. Seurat mentions the presence of a buccal 

 cavity between the lips and oesophagus. I was not able to detect 

 any such space in my material except in one. Ph. gracilis, sp. n., 

 where I think the space was due to contraction ; in all my other 

 specimens the oesophagus immediately followed the lips. 



The nerve ring is large, and encircles the muscular oesophageal 

 portion in its posterior half. 



The intestine is straight, and its connection with the oeso- 

 phagus is slightly thicker than the rest of the organ, which has 

 a uniform thickness throughout. It opens to the exterior by a 



