JAPANESE PALOLO, CEÏtATOCEPHALE OSAWAI, N. SP. 15 



tlie oOtli parapodium, in which they reach the maximum length 

 (the blade length being about twice that in the 30th parapodium) ; 

 after that they again gradually become shorter towards the 

 posterior end of the body. 



The ventral cirrus is best developed in the anteriormost seg- 

 ments, gradually becoming smaller in those more posteriorly situated. 



The " Spinndrüsen " of Ehlers are found in the superior 

 ramus. This gland begins to appear in the 22nd-25th parapodium. 

 In Woodcut 3 the outline of it is indicated by a dotted line. It 

 is somewhat pear-shaped and occupies a great portion of the 

 ramus. In the more posteriorly situated parapodia it may even 

 extend into the body beyond the basal constriction of the para- 

 podium. Externally it opens by a short duct at the base of the 

 dorsal cirrus. It is largest in about the 35th parapodium. 



Here I may state that the locomotion of the worm is effected 

 by alternate forward and backward movements of the parapodia 

 on both sides of the body, assisted by forcible protrusions of the 

 chitinous appendages, which are retractile to a certain degree. 

 It has seemed to me that in the forward motion of the worm 

 the setose bristles come more into operation than the falcate, 

 and vice versa in the backward motion, as for instance in the 

 act of retreating into the burrow. 



Pygidium. — This is about as long as it is broad, the length 

 being about equal to that of the three preceding segments taken 

 together. The center of the rounded hind end is occupied by 

 the anus, which shows a radial wrinkling around it. The pygidium 

 is devoid of parapodia but is furnished with a pair of colorless, 

 slender and delicate anal cirri, which, arising from its ventral 

 posterior end, are directed backwards, 



