180 22 



Ascoglossa. 



Plakobraiiclms, van Hass. 



R. Bergh, malacolog. Unters. Heft. III. 1872. p. 115—174. Taf. XVII— XX. — IV. Abth. 2. 1900. p. 206-208. 

 — , neue Nacktschneeken d. Südsee. I. Journ. d. Mus. Godefroy. Heft. II. 1873. p. 12—15. Taf. IX, 

 Fig. 5, 6; Taf. X, Fig. 22—25; Taf. XI, Fig. 3—6. 



Plahobranchus ocellatus, van Hass. 



PL ocellatus. van Hass. Allg. Konst-en-Lelter-Bode voor het jaar 1824. I. Deel, No. 3. p. 24 — 35. 

 PI. argus, Bgh., 1. c. 1872. p. 151-165. Taf. IX, Fig. 6—9; Taf. XVII, XVIII. 



PI. II. Figs. 13—14. 



At Koh Kahdat, on Febr. 19 lh 1000, was fished a specimen creeping on sargasso. 



This specimen had in spirit kept a length of I5 mm , by a breadth of 6'5 mm , and 

 a height, with the lobes raised, of 4'5 mm . — The colour all over the back and on the 

 inside of the foot-lobes was white; at the fore end of the pericardial protuberance and 

 still more numerous at the fore part of the back, small reddish yellow eye-spots were seen 

 with light centra; also the sole of the foot was white with rather numerous, spread, small 

 and quite small, round black spots. The furrow of the (highly contracted) tentacles , and 

 the fore edge of the head were black, and above the edge a series of (4) somewhat larger, 

 black eye-spots were seen. At the edge of the dorsal lobes a series of (16 — 17) similar 

 black eye-spots were seen, and the other parts of the outside of these lobes were covered 

 with small reddish yellow eye-spots which imparted to the whole region a reddish 

 yellow colour. 



The form was as usual. The eyes which are situated beside each other, were 

 indistinctly transparent in the neck. At the pericardio-renal, median protuberance the fore- 

 most smaller part containing the ventricle of the heart, was rather strongly separated from 

 the hindermost part with the auricle and the kidney. Not far from the right edge of the 

 pericardium the small whitish anal papilla was seen; more backward the renal pore 

 appeared. The dorsal folds and the folds on the inside of the dorsal lobes were as usual, 

 neither did they reach quite to the end of the body. The number of folds before the 

 middle of the body was about 43 Immediately at the base of the right tentacle the male 

 genital aperture was seen. 



The central nervous system showed, as before described, the roundish cere- 

 bro-pleural ganglia and the pedal ganglia, as well as the (3) visceral ones situated between 

 the latter: on each side a smaller one, and between these a larger one (gangl. azygum). — 

 The eyes that are situated close to each other, had a diameter of O-le™ 11 ; as before men- 



