THE GEPHYREA OF .TAPAX. 9 



the ganglion, and is not provided with contractile villi. The 

 intestinal convolution (ic) is formed of 6-10 double spirals which 

 are more or less irregularly twisted around the fine spindle- 

 muscle {sm). The latter is fixed to the body-wall at both its 

 anterior and posterior ends. Its anterior end is at a considerable 

 distance anteriorly from the anus. There is only one fixing 

 muscle (fm), connecting the hind end of the œsophagus (near the 

 commencement of the convolution) with the body-wall on the left 

 side of the nerve-cord and a short distance in front of the orio-in 

 of the ventral retractor muscles. No blind diverticulum is present 

 on the rectum. The latter is supplied with wing-muscles {w7n). 

 The segmental organs (so) exhibit a peculiar structure unknown 

 in other Sipunculids. Each of them consists of two long lobes 

 equal in size and shape, the one being directed anteriorly and 

 the other posteriorly. The two lobes are directly continuous with 

 each other. At their boundary lies the external aperture, the inner 

 aperture or the funnel being found at the basis of the anterior lobe. 

 The organs have a reddish yellow color. Their wall is very thin. 

 Habitat : The animals are discovered under sea-weeds cover- 

 ing a tufaceous sandstone between the tide-marks. They have 

 hitherto been collected only on the shores near the Misaki 

 Marine Laboratoi'v, where however thev are rare. 



PHASCOLOSOMA OKINOSEANUM, n. sp. 



(Figs. 4, 34-38). 



In March, 1901, a single specimen of the species here dis- 

 cribed as new under the above name was dredged at a depth of 



