ON PTYCHODERA FLAVA. 167 



after being kept for a short time in captivity they discharge 

 the sand, and the larger specimens may then stretch them- 

 selves out to a length somewhat exceeding 5 inches. The 

 collar region may be upwards of a quarter of an inch in 

 length, while the proboscis is normally somewhat shorter. The 

 relatively great length of the collar region is characteristic of 

 the genus Ptychodera. The gill-region measures from half 

 to three quarters of an inch in lengthy being about as long as 

 the proboscis and collar regions put together. The hepatic 

 region may measure about one and a half inches. 



Eschscholtz correctly described the body as presenting 

 numerous transverse folds or annulations. When the intestine 

 is free from sand and the body is consequently not swollen 

 out^ these annulations are very prominent ridges, and are 

 characteristic for the species. They are not continuous all 

 round the body, but are interrupted along the dark yellowish 

 or reddish-vellow coloured lines which mark the course of the 

 dorsal and ventral nerve-cords. Here and there, especially in 

 the posterior dorso-lateral region, the annulations are sub- 

 divided into islets. The more faintly marked ridges on the 

 outer surface of the genital pleurae are often similarly sub- 

 divided and also branched. 



On either side of the dorsal nerve-cord may be seen a dark 

 longitudinal band corresponding in position to the ciliated 

 grooves in the intestinal wall, described by Spengel in other 

 species, and more recently by HilU in P. australiensis. 



But these externally visible lines do not cause any interrup- 

 tion in the annulations or islets of the integument, as they do 

 in P. australiensis, according to Hill's description, and as 

 does the single asymmetrical band, present only on the left 

 side, in P. minuta, as described by Spengel. 



As indicated by the specific name, flava, the colour of this 

 species is a nearly uniform dull yellow, somewhat deeper in 



' Jas. P. Hill, "Ou a New Species of Euteropneusta (Ptychodera 

 australiensis) from the Coast of New South Wales," 'Proc. Linu. Soc. 

 New South Wales,' vol. x (2), 1894. Id., " Preliminary Note on a Balano- 

 glossus from the Coast of New South Wales," ibid., vol. viii (2), 1893. 



