35 223 



and with regular longitudinal folds which are especially conspicuous on I he loot. 

 Wheel-organ a slanting cilia-covered disc, surrounded hy a wreath ol sonicwiial 

 longer cilia and with a broad bunch of long cilia on the top; no visible auricles. 



No mastax; as a remnant of the alimentary canal a longitudinal folded sac- 

 like body lying over the testis and fastened by ligaments to the body wall. Brain 

 large with a broad red eye; a dorsal antenna with a bunch of short bristles; no 

 lateral antennæ have been observed. Four longitudinal muscles. Very conspicuous 

 are six transversal muscle bands which regularly contract and expand the I)ody; 

 during swimming and creeping this is always altering its form. The two lateral canals 

 carry each three vibralile tags; no conlractile vesicle visible. A very large pyrilorni 

 testis with two sorts of spermatozoa; a long ductus seminalis covered with cilia; 

 penis short ending dorsally upon the second foot segment; cilia coating round the 

 opening; two short foot glands. — 



The descriptions of Wesché and myself do not agree very well but as there 

 is also considerable discrepancy between his drawings and his description a com- 

 parison is difficult. 



Size of male 120 /(, of female 300 — 400 p. Time: April. Several times I have met 

 with this slowly swimming or creeping animal. It appeared rather often in cultures 

 which contained only N. naias; the very thick foot and no, or at all events very 

 small, auricles are both characters which the male shares with the female. 



Notommata aurita (Müll.) 

 Talj. I, lig. 3. 

 Description. Body subcj'lindric, ventricose, furnished behind with a shoi't 

 tail, by no means so conspicuous as in the female. Cuticula thin, extremely flexible, 

 altering in form with a peculiar, rather constant system of longitudinal lines dorsally; 

 the course of these lines will best be understood from the figure. Foot short with two joints, 

 well separated from the body; two rather short acute toes. Wheel-organ a cilia-co- 

 vered slanting disc of triangular form, surrounded by a wreath of rather short cilia. 

 Seen dorsally the wheel-organ presents itself as bent inward; there are two well- 

 developed auricles. Alimentary canal absent; as rudiment above the testis a rather 

 inconspicuous sac or band. Brain very large, broad, with a large llatlened eye, a 

 conspicuous dorsal antenna lying remarkably near the wheel-organ. Of the retrocere- 

 bral organ a very conspicuous opaque part containing a large number of concrements; 

 further two subcerebral organs which I have not been able to see in so conspicuous 

 a position that I have ventured to draw them ; they are concealed between the six 

 large cells of hypodermal nature and are indicated in the figure. That they really 

 exist, is so much the more probable, as shortly before the death of the single speci- 

 men I have seen, I with certainty observed two rounded openings which most pro- 

 bably are the openings of the organ. The lateral antennæ I have not been able to 

 see. Two lateral canals with three vibratile tags each, but no contractile vesicle. 



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