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 

 ^■entro-lateral regions of the body terminate on its lower margin. 

 According to Spengel, a similar epidermal stripe exists in Pt. 

 minuta, 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 PL australieiisis may be taken as a character 

 of specific value. 



Behind the termination of the epidermal stripes the tail region 

 l)ecomes 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 posteriori}' into slaty green, and this again into a deep 

 lirown in the region of the larger cteca, 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 ma}'- be 

 here mentioned that a large proportion of the individuals of this 

 species are infested by a parasitic C^opepod 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. Mitth. Zool. Stn. Neap. Bd. i. p. 

 515. 



