THE ANATOMY OF ONCHOLAIMUS VULGARIS, BAST. 103 



and 2), whicli is square in profile, rapidly to the posterior, 

 Avhich forms a rounded and rather blunt cone (PI. 7, fig. 5). 



The animal is quite transhicent ; the only pigment present 

 is in the intestinpJ wall, golden-brown granules arranged in 

 patterns, which produce a tesselated appearance, and are 

 sometimes sufficiently abundant to cause the animal to 

 appear of a brown colour, even to the naked eye. 



The mouth is terminal, and is surrounded by three very 

 flat papilla3 (PI. 7, fig. 2, a). 



Immediately behind the latter is a ring of short setfe 

 (ibid., h), while smaller hairs are scattered over the anterior 

 portion of the body, and arranged along the dorsal (c) and 

 ventral lines. 



The anus (PI. 7, fig. 5, cl. ap.) is subterminal, 'IbS mm. 

 from the tail, in the midventral line. 



The cellular character of the longitudinal lines (PI. 7, fig. 

 1, MDL, LC, mvl) and the striation of the muscle fields (PI. 7, 

 fig. 5) are obvious. Prominent objects also are the cup- 

 shaped pharynx, with its three teeth (PI. 7, fig. 2) ; the oeso- 

 phagus (PI. 7, fig. 1) ; surrounded by the oesophageal 

 ring and collar of ganglion-cells (PI. 7, fig. 1) ; the pigmented 

 intestine; the hyaline dncts of the tail glands filling up the 

 post-anal region (PI. 7, fig. 5) ; the ventral gland in the male, 

 opening "112 mm. in front of the nerve-ring; and the large 

 cells of the body space which generally lie in the submedian 

 lines (PL 7, fig. l,a). 



The gonads occupy a large part of the body in either sex, 

 but are more conspicuous in the female; the large chalk- 

 white ova (text-fig. 2, ov., p. 124) in the uterus can be distin- 

 guished even with the naked eye. Under a low power the 

 central vulva(r!(.) surrounded by the cellular mass of vulvar 

 and vaginal glands and the elongated ovaries (ovr.) running 

 alongside the uteri can be seen. 



In the male the gonads appear as a fairly uniform cellular 

 cylinder opening posteriorly in common with the gut. Here 

 also are to be found the sabre-shaped spicules (PI. 7, fig. 5, 

 sp.) with their central accessory piece. 



