210 THE GROUSE IN HEALTH AND IN DISEASE 



and when protracted they are divaricated. When in this extruded condition they 

 form a cross, the left spicule projecting to the right and vice versa. Besides the 

 spicules and between them, rather to the posterior end, lies the accessory or median 

 piece, which Looss calls the " gubernaculum." It is best seen in profile, and has 

 then somewhat the outline of a Turkish slipper. It also has muscles inserted into 

 its ends. 



Near the base of each spicule is an oval clear vesicle ; but apparently the end of 

 the spicule was outside and not inside the lumen of the vesicle. 



The head presents very little signs of differentiation. In some specimens with 

 a one- twelfth objective three very minute lobes can be seen, but they are not 

 visible in all cases, and their appearance may be due to some expansion of the 

 mouth. The mouth is terminal and leads into a slightly bulb-like cavity which 

 soon narrows into the thin capillary lumen of the alimentary canal. The oesophagus 

 is more granular than the intestine, and separated from it by a very shallow 

 groove ; its walls consist of flatly rounded cells with conspicuous nuclei. I could not 

 detect any parts in the intestine ; it appears to be an undifferentiated tube running 

 from mouth to anus, the lumen lined with chitin and the walls formed of granular 

 cells with visible nuclei. No food was seen in the alimentary canal. Posteriorly 

 the intestine widens into a spacious rectum, which just in front of the anus narrows 

 again into a short, thin, terminal portion. The anus in the male opens into the 

 genital bursa ; in the female it is a little distance in front of the end of the pointed 

 tail, but relatively not so far forward as it is in the larva. Two cervical glands 

 run about a fifth of the length of the body backwards, and end with rounded ends 

 about the same level. 



In the male the testis begins about the level where these glands end. It 

 consists of a single tube, the cells lining which give rise to the spermatozoa. 

 Anteriorly the cells when squeezed out seem amoeboid, with rounded and very 

 refringent nuclei. The hinder end of the testis is, however, crowded with 

 spermatozoa shaped like little squat bottles, and in some specimens the genital 

 bursa sheltered two clumps of these, looking as though they had escaped from the 

 two vesiculse seminales. 



I saw nothing of excretory canals or their opening, and unless an ill-defined 

 ring which surrounded the alimentary canal about one-twenty-fifth of the body- 

 length from the anterior end be the nerve-ring, I saw nothing of the nervous 

 .system. 



The ovaries are double. Each tube arises about the level or a little behind the 



