226 DISCOVERY REPORTS 



2-5 mm. broad was found. The worm to which this belonged must have been 30-40 cm. 

 long. A thin transparent tube was sometimes secreted when the worms had been in 

 captivity for a few hours. 



Form and colour in life. The body is round in section, but it tapers and is a little 

 flattened from above down towards the tail. The head is round in outline from above, 

 broader than it is long, and about one and a half times as broad as the body. The pro- 

 boscis pore is just ventral to the tip of the head and the mouth is a small longitudinal 

 slit immediately behind the junction of the head and neck. There is a large laterally 

 spread group of black pigment specks at the edge of the head on each side of the pro- 

 boscis pore. The tail is somewhat bulbous ; its margin is nearly transparent, and the gut, 

 which shows through, is not swollen. 



The general colour is brownish red, fading gradually to yellow at the tail. The under- 

 side is paler than the back, more so posteriorly. The shades of red vary from dusky 

 crimson to light yellow red. The colour fades abruptly near the tip of the head and there 

 is here a transverse white mark nearly complete ventrally to form a white ring. The first 

 body ring occurs about the breadth of the head from its posterior end. This ring is a 

 white chevron with its apex pointing back. It is incomplete ventrally. The rest of the 

 body is marked by a series of white annulations also usually incomplete ventrally. The 

 number varies from seventeen to eighty. Some of the earlier rings are complete and the 

 larger ones are formed of two narrow bands placed close together. The interval between 

 the third and fourth body rings is more than double the interval between any other 

 consecutive rings. Traces of lateral longitudinal white lines are found, and sometimes 

 there is a thin mid-dorsal line traceable after the first few rings behind the head and dis- 

 appearing again at about the fortieth ring. 



Form and colour of preserved specimens. On fixing shrinkage takes place, but the body 



retains its shape to a great extent. The head is flattened but very round in outline from 



above. There is a fold between head and body in which are hidden the 



openings of the canals of the cerebral organs (Fig. 1). Side organs are 



present. They appear as white marks one on each side of the body in 



the dark brown region behind the third white ring. The body is often 



somewhat swollen here. The colour of the body anteriorly is light brown 



on the back, paler beneath. There is a sharp transition after the second 



white ring to dark dirty brown which is similar dorsally and ventrally. ', D .. 



° J J J nothus, Burger. 



This gradually fades and at the eleventh ring the colour is again light Head of preserved 

 brown. Lateral white lines can just be seen. The patches of eyespecks specimen, ventral 

 are sometimes visible as a greyish blur. surface. 



Internal structure. The epithelium is thick, especially in the oesophageal region, and 

 contains numerous eosinophile gland cells. Near the tip of the head the distribution of 

 these cells is unequal, there being many ventrally and few dorsally while with the pig- 

 ment cells the opposite is the case. Head glands and frontal organs are not present. The 

 mouth is evident in transverse section before the brain has disappeared (Fig. 2 A). The 

 gut is unbranched. 



