BY WILLIAM A. HASWELL, M.A., B.SC. 261 



Erscheinung beobachtete ich an dem Sacke, das ist seine Con- 

 tractilitat, welche vielleicht durch Elemente musculoser Natur, 

 die der Wand eingebettel sind, veranlasst wird * * * In 

 einem Falle bestand der Inbalt der Segmentalorgane aus blasen- 

 iihnlichen Korpern, von 0-012 — 0*024 mm. Grosse, die fettartige 

 Kornchen enthielten ; sie bildeten an der Innenflacbe des Sackes 

 eine ungleichmiissig vertheilte Masse, die bei auffallendem Lichte 

 weiss aussah." 



Two species of Polyno'e wbich occur in Port Jackson — viz. 

 P. {Antinoe) praclara and F. {Antinoe) Wahlii — seem to be near 

 allies of P. {Antinoe) peUucida. In these the intestinal ceeca 

 (PL vi., fig. 1.) consist of a ventral portion, which is a rounded 

 non-contractile sac, and a dorsal portion which is contractile* 

 sometimes with a regular rhythm, and is also undivided externally 

 (though internally partitioned), but presents rounded elevations 

 of its outer wall. The latter portion occupies the cavities of the 

 scale-tubercles, the bases of the dorsal cirri, and the bases of the 

 parapodia. They are found from the second segment backwards 

 though not in all the segments of the anterior region of the body. 

 These cseca are connected with the alimentary canal by a ciliated 

 neck, which is very long in the anterior segments and very short 

 behind, and the opening into the alimentary canal is funnel- 

 shaped and thickly ciliated. The caeca are connected with the 

 walls of the parapodia by bands of muscular fibres. In the 

 anterior segments they are almost colourless ; behind their walls 

 are of a bright golden yellow owing to their containing numerous 

 yellow cells. 



Ehlers' drawing (1. c, taf. iv., fig. 3.) is a very faithful repre- 

 sentation of one of these caeca as seen in Polyyioe prceclara save 

 that the internal orifice of the supposed segmental organ is 

 represented as opening into the body-cavity instead of into the 

 intestine, and the bands of muscular fibres connecting the caecum 

 with the walls of the parapodium in the neighbourhood of the 



