The Araiifulidce of South Africa. 21 



The vascular system is practically identical with that of 

 A. marina. 



The margin of the ventral lip of each nephridial funnel is frilled 

 and its internal face marked with ridges which converge towards the 

 bottom of the funnel. This condition of the ventral lip is so con- 

 stantly met with in this species that it may be looked upon as 

 specific. The dorsal lip bears the usual fringe of triangular, 

 vascular, ciliated processes. 



The gonads are small, as in A. marina. 



The brain and nerve cord are similar to those of ^-1. manna. 

 Statocysts are present and may be found in dissections of the 

 anterior end. They are situated nearer to the brain than in A. 

 marina. Each statocyst opens to the exterior but the pore is very 

 difficult to find,* it is situated just under the extreme antero-lateral 

 margin of the prostomium. In nearly all preserved specimens the 

 peristornial region is contracted, and the pore, which lies at the 

 bottom of a groove, is not visible. In well-extended specimens 

 the small aperture will be found in the position indicated in Text- 

 Fig. V., S. 



The statocysts are large ; in a specimen about 70 mm. long their 

 three diameters are about '2 mm., -18 mm., and - 15 mm. respectively. 

 From each vesicle a moderately wide tube passes out laterally and 

 turns forwards to open externally near the lateral margin of the 

 prostomium, as described above. Each statocyst contains about a 

 score of statoliths, which consist, for the most part, of sand-grains 

 together with a few fragments of sponge spicules. The statoliths in 

 this specimen are practically naked. The peristornial wall of another 

 specimen was stained, cleared, and examined as a whole mount ; 

 each of the sand-grains and spicule-fragments in this statocyst has 

 received a thick chitinoid envelope, secreted by the gland cells in the 

 wall of the statocyst, so that the resultant statoliths have rounded 

 outlines. In the former specimen the canal of the statocyst is 

 widely open throughout its length, so that the cavity of the 

 statocyst is in free communication with the exterior ; in the latter 

 specimen the passage is occluded at one or more points, and closure 

 of the statocyst has thus been brought about a condition invariably 

 found to be correlated with the presence of coated statoliths such as 

 those above described. 



* A binocular dissecting microscope is almost indispensable for making exami- 

 nations for the openings of the statocysts and nephridia and other minute 

 features. 



