BY JAS. P. HILL. 
3 
The largest specimen found during my last collecting trip in 
May was a sexually mature male, measuring, in the living condi- 
tion and when only very moderately extended, about 12 cm. in 
length with a breadth in the tail region of 7*25 mm. In August 
of last year, I found another large specimen which measured in 
the contracted condition about 18 cm. In the fully extended 
condition, this specimen, now in the teaching collection of the 
Biological Department of Sydney University, reached a length of 
over 25 cm. The majority of the animals were, however, very 
much shorter and thinner. They are capable of very considerable 
extension; for example, one specimen whose tail region had a 
transverse breadth of only l - 75mm. reached in the fully extended 
condition a length of 11*7 cm. 
Proboscis : The proboscis is relatively short like that of Ft. 
minuta and PL sarnie tisis. It varies in shape and length during 
life; when the animal is progressing it is more or less elongated, 
and when at rest generally somewhat egg-shaped, the latter being 
the shape it almost invariably takes when the animals are 
preserved in chrom-osmic acid. The proboscis of the first large 
specimen referred to above had a length of about 10 mm. in the 
living condition. 
Collar: In the living animals the surface of the collar is smooth 
and in them, as well as in preserved specimens, it can readily be 
divided into the five characteristic regions (fig. 1). The first region 
includes slightly more than the anterior half of the collar, and is 
formed by the anterior free part of the latter. It spreads out 
anteriorly, investing the neck and base of the proboscis like a 
frill with margins crinkled as well during life as in preserved 
specimens. Behind the frill-like anterior region the collar is 
strongly contracted to form a well marked circular groove — the 
second region [figs. 1 and 15 (2)] — the anterior margin of which 
lies immediately above the mouth aperture. This groove is 
slightly more marked on the ventral side than on the dorsal. 
The groove is followed by a prominent circular cushion of a 
lighter colour forming the third region [figs. 1 and 15 (3)]. Behind 
