hY VEHA A. IRWIX-SMITH. 783 



tributed of the New South Wales species. I have found it in 

 the same niatei'ial witli each of the otlier three species; and, in 

 additi(jn, at nearly every s})ot, where a search has been made, to 

 a distance as far up the harbour as Circular Quay, and to a 

 depth oi 18 feet below low water-mark. No collections were 

 made at a greater depth than this; and the majority of the speci- 

 mens were obtained just below tide-marks. 



I have been able to observe a fairly large number of living 

 individuals. In one case, all the specimens were found alive in 

 material which had been collected four days previously. Two 

 were kept- alive for fourteen days in a crystal-dish, by changing 

 the water every day; and were then accidentally crushed during 

 an examination under the microscope. A third worm, a young 

 specimen, was kept alive for five weeks; and was still active, and 

 apparently quite healthy, when it was lost during transference 

 to fresh seaw^ater. It had not then reached mature size. All 

 the specimens found alive were very dirty, being covered with 

 grit. They required frequent cleaning with a very fine camel's 

 hair brush, as it was found that they continued to accumulate 

 grit every day during the time they were alive, the dirt appa- 

 rently adhering to a sticky secretion over the whole surface. 



Ch. haswelli is the largest of the species found here. The 

 length of the largest male obtained was 1*32 mm., and of the 

 largest female, l"44mm. Sexual organs had not developed in 

 the smallest specimen found, which was 0*60 mm. long. The 

 worms are mostly S-shaped when fixed (PI. xlvi.). They are long 

 and slender, and narrower, in proportion to their length, than 

 the other species. The females are, on an average, longer than 

 the males; and, in both sexes, the head is broader than the 

 average width of the trunk. In the male, there is very little 

 variation in the width of the trunk, though there is a sliglit 

 increase in size in the middle region. The female is markedly 

 wider in the middle. Typical measurements are given in the 

 accompanying Table p. 7 98). 



The head is oval in shape, and well marked off from the rest 

 of the body. In length, it is only one-ninth to one-tenth of the 



