■36 



ON A NEW SPECIES OF ENTEROPNEUSTA {PTYGHO- 



DERA AUSTRALIENSIS) FROM THE COAST OF 



NEW SOUTH WALES. 



By James P. Hill, Demonstrator of Biology, University of 

 Sydney. 



{Abstract.) 



The name Ptychodera australiensis is proposed for the first 

 described Australian species of Enteropneusta. It is like other 

 species of the genus, littoral in its habits, and occurs in consider- 

 able abundance at certain points along the coast of New South 

 Wales. 



Individuals vary very much in size; the largest specimen found 

 measured when fully extended over 25 cm. in length, but the 

 majority are very much smaller. The two sexes can readily be 

 distinguished from each other by the different colouration of the 

 sexual glands. In the. males the testes are of a very deep yellow, 

 or in some cases of an orange colour; while in the females the 

 ovaries are of a light yellow or almost whitish colour. In both 

 sexes the proboscis is of a light yellow colour, the collar of a 

 slightly deeper yellow, while the tail region is almost colourless. 



The species is especially characterised externally l)y the great 

 development of the genital wings, which completely hide the gill 

 area and extend far into the hepatic region, and by the presence 

 of two longitudinal epidermal stripes extending over the anterior 

 two-thirds of the tail region, and overljnng the two ciliated bands 

 of the intestine. The liver sacs present a distinctly paired 

 arrangement in two longitudinal rows. The number of sacs 

 averages lietween 40 and 50 on each side, but there may be as 

 many as 60. 



In the mode of formation of the proboscis pore Pt. australiensis 

 appears to be the most variable of all Enteropneusts hitherto 

 described. In the majority of the individuals examined the pore 



