77G J. H. ASHWOKTH. 



body-cavity. These are large^ and measure across their flat 

 faces 0-2 x 0\17 mm. (see pp. 747 and 758j. 



The anterior end of one of the specimens was cut into sections. 

 A pair of large otocysts is present (fig. 14). They are much 

 larger than those of the Otago specimens and a little larger 

 than those of the worms from Uschuaia (cf. figs. 13, 14, 15). 

 Their three diameters are respectively about 0'36, 0*38, and 

 0'28 mm. (compare the measurements on pp. 752 and 759). 



The otoliths are all spherical or neai-ly so, and are com- 

 posed of a yellowish or brownish secreted substance. There 

 are in each otocyst two otoliths (fig. 14) considerably larger 

 than the rest. They are about 0'055 mm. in diameter, and in 

 the centre of each is a small irregular foreign body, probably 

 a quartz-grain. The smaller otoliths are usually from 0'02 

 to 0*03 mm. in diameter, and only rarely is a foreign particle 

 visible in them, though doubtless each has a very minute 

 central nucleus of this description. The two large otoliths 

 described above are probably the first otoliths of the post- 

 larval stage, which always remain distinguished by their 

 greater size from those which are formed later. A similar 

 condition exists in A. ecaudata, in the post-larval stage of 

 which there is for some time only one otolith, which always 

 remains conspicuous, owing to its larger size (Gamble and 

 Ashworth, 1900, p. 504 and fig. 64). 



The otocyst- opens to the exterior by a tube, the external 

 opening of which corresponds in position to that of the Otago 

 specimens and of A. marina. The lumen of the tube is of 

 moderate size along the greater part of its length, but is 

 reduced near its entrance to the otocyst in one case to a very 

 narrow passage, and in the other is practically obliterated. 

 The wall of the tube is renuirkable for the presence of 

 large gland-cells, which are practically confined to the dorsal 

 wall. They are almost ovoid in shape, and their cell- 

 contents are in the form of a reticulum. In the ventral 

 wall of the tube there are numerous elongate fusiform sense 

 cells. 



The remaining structures shown in sections of the anterior 



