BY JAS. P. HILL. 
7 
of epidermal gland cells. The groups occupying the dorsal surface 
of the body extend between the upper margin of the epidermal 
stripe and the dorsal median line, while those occupying the 
ventro-lateral regions of the body terminate on its lower margin. 
According to Spengel, a similar epidermal stripe exists in Pt. 
?ninuta, but in correspondence with the single ciliated groove on 
the left side, only on that side, so that the presence of two 
epidermal stripes in Pt. austr alien sis may be taken as a character 
of specific value. 
Behind the termination of the epidermal stripes the tail region 
becomes gradually somewhat narrower to its posterior end, in 
which is situated the terminal anus of varying outline. 
Colouration: The sexually mature males and females can 
very easily be distinguished from each other by their different 
colouration. In both sexes the proboscis is of a light yellow 
colour, while the collar is of a slightly deeper yellow. In the 
males the testes are of a very deep yellow colour, or less frequently 
in some individuals of a deep orange. In the females the ovaries 
are of a very light yellow or almost whitish colour. The females 
are on the whole of a lighter colour than the males. 
The most anterior liver sacs are of a brownish colour which 
passes posteriorly into slaty green, and this again into a deep 
brown in the region of the larger ca3ca, this brown colour being- 
retained more or less completely in preserved specimens, while the 
other sacs lose their colour entirely. Posteriorly the sacs again 
assume a slaty green tinge. The tail region is whitish in colour 
and its walls transparent, readily allowing the sand particles in 
the intestine to show through. 
This species is destitute of any odour. Incidentally it may be 
here mentioned that a large proportion of the individuals of this 
species are infested by a parasitic Copepod belonging to the genus 
Ives of Mayer,* but whether it is identical with the single 
member of the genus hitherto described, Ives balanoglossi, I am 
* Ein neuer parasitischer Copepode. Mitfch. Zool. Stn. Neap. Bd. i. p. 
515. 
