1903.] OLIGOCHiETA FROM NEW ZEALAND. 213 



p. 233), and indeed agrees with that of certain of the Naididse, 

 such as Stylaria lacustris *, though I should place Clitellio at a 

 lower grade even than B. coccinea, for in it apparently, and at 

 any rate in the new genus, the atrium is still simpler, and 

 approaches that found in JVais elinguis, or in De7'0, or in Chceto- 

 gaster. In the first named, Stole t shows the atrium as a 

 dilatation of the sperm-duct, from which it is not distinctly 

 marked ofi"; its lining appears to consist of low, cixbical cells 

 (? glandular), outside which is a layer of flat, peritoneal cells. 



In the atrium of Chcetogaster^ as described and figured by 

 Yejdovskyt, the glandular lining and flat epithelial cells are 

 distinctly shown ; while Beddard § thus describes the organ in 

 Dero: — "The atria are lined by a columnar epithelium, but I 

 could observe no layer of cells covering this organ externally 

 and forming the structure which has sometimes been termed 

 prostate." 



In these forms, and in Taujyodrilus, the atrium, indeed, is in 

 its most simple form, as a distinct and definite organ — definitely 

 marked off from the sperm-duct, but still, evidently, a dilatation 

 of its distal extremity, 



LiMNODRiLus VEJDOVSKYANUS, sp. n. (Plate XXY. figs. 10-17.) 



From Lake Waikare I received about two dozen stout, gi'eyish 

 worms, in which the ciiticle is much wrinkled, the body-wah thick, 

 and the segments distinctly bi- and tri-annulate. 



The prostomium is conical, with a rather acute point ; it is 

 relatively long, and exceeds the length of the first segment. 



The chcetce are in the usual four bundles : 4 and 5 per bundle ; 

 even 6 in the bundles of segments ii. to vi. ; but throughout the 

 greater part of the body there are 4 ventrally and 3 dorsally. 



The dorsal chtetse are slightly smaller in all dimensions than 

 the ventral, but in form they are similar (PI. XXV. figs. 10, 11). 

 The upper tooth is very distinctly longer and less robust, and 

 has a sharper point than the lower tooth. 



The ventral chsetse are absent on segment xi. 



The clitellum covers segments xi. and xii., and does not 

 encroach at all on segment x. The genital pores have the usual 

 position. 



Internal Anatomy. 



This was studied both in entire specimens — stained in alum- 

 cochineal, and mounted in Canada balsam — and in serial transverse 

 and longitudinal sections. 



The alimentary canal is without a distinct muscular pharnyx ; 

 the buccal region passes through segment i. into the commence- 

 ment of segment ii. ; its wall is here folded and provided with a 

 few retractor muscles. Following this is the beginning of the 



* Vejdovsky, Syst. u. Morph. cl. Oligoch. 1884, pi. iv. fig. 10. 



t Stole, SB. Bohm. Ges. 1887, p. 228, fig. 7. 



X Vejdovsky, Syst. u. Morph. d. Oligoch. 1884, pi. v. fig. 7. 



§ Beddard, P.Z.S. 1889, p. 444. 



