ASHWORTH, AN ACCOUNT OF ARENTCOLA LOVENI KINBERG. 13 



of A. cristata, the pouches never perforate the second septum 

 but lie entirely in front of it. The function of the septal 

 pouches is unknown but it has been suggested that they aid 

 in the e version of the »proboscis». 



The powerful retractor muscles of the pharynx (Ph. R.) 

 pierce the first septum; they arise from the body wall a short 

 distance anterior to the level of the second chaetigerous an- 

 nulus. 



The second septum (S-) is thin and, in each of the spe- 

 cimens examined, is pierced by two apertures of considerabJe 

 size, one to the right and the other to the left of the 

 oesophagus. These two apertures permit the passage back- 

 wards of the two septal pouches. 



The third septum (S^) is well developed. In one of the 

 Saldanha specimens, in which it has been examined in detail, 

 this septum is marked on its anterior face with small brown 

 or black spöts, each due to the presence of excretory gran- 

 ules in certain groups of cells. On its posterior face the 

 septum bears numerous slender branching vessels, 30 — 40 {j. 

 in diameter, covered w^holly or partly with chlorogogenous 

 tissue. The ultimate branches of the blood vessels end blindly. 

 The septum is apparently perforated, like that of A. marina, 

 but the apertures are difficult to see as they are masked by 

 the felt work of blood vessels above described. 



The setal musculature is of the usual type except that 

 the three anterior notopodia have either no retractor or only 

 a very short one, 2 mm. or so in length, which arises from 

 the body wall just ventral to the notopodium. A few of the 

 other notopodia also have a similar short retractor instead 

 of the usual long retractor strand inserted at the side of the 

 nerve cord. 



The strap-like oblique muscles (M. Ob.), which arise at 

 the sides of the nerve cord and are inserted about the level 

 of the upper end of the neuropodia, commence in the Sal- 

 danha specimens immediately behind the third septum; in 

 the type specimens the most anterior oblique muscles are in 

 the fourth chaetigerous annulus. 



Alimeiitary caiial. 



The alimentary canal presents the usual regions, pharynx 

 (Ph.), oesophagus, stomach (St.) and intestine. On the post- 



