30 



many layers. Papillae almost entirely absent. 3 Ventral folds. Radula distichous, very large; 

 broad bands with small teeth, close against the pharyngeal wall. Radula-sac very spacious and 

 invaeinated. 2 Globular salivary gdands, without lumen or efferent canals. Cloaca-ducts without 

 appendages, hut winding and considerably widened. 3 Small copulation-spicula. A circlet of gills 

 in the cloaca. 



10. Cyclomenia holosericea nov. spec. (Plate Y figs. 146 — 171). 



Stat. 300. io°48'.6S., [23 23'.! E. E. coast of Rotti, to the west of Ti mor. In fine grey mud. 



918 M. 1 Specimen. 



about 20. 



Length 1 3 mm. Bronze-coloured with dark ring at the anterior part. Xumber of gills 



o. 



1 Specimen trom the East-Indian Archipelago. 



It is represented in fig. 146, 4 times enlarged. The length is 13 mm. At the anterior 

 end the diameter is 2 mm., at the posterior end 1,5 mm.: average diameter 1.75 mm. The 

 length-index is therefore about 7. The shape of the animal is cylindrical ; the sections are 

 perfectly round ; hence the name. The anterior extremity is broad and bhmt at the end. The 

 ventral groove is distinct, the mouth-opening slit-like. The colour is dark grey, somewhat greenish 

 or bronze. At the anterior end a dark ring is noticed. The animal is not shining, but velvety; 

 spicula are not visible. 



The spicula (fig. 147) are of the Proneomenia-shape : hollow, straight or S-shaped (A); 

 along the ventral groove they are broad, though thin and very transparent (B). 



The cuticle is rather thick and transversed by spicula in various directions (fig. 148). 

 The hypódermis is only 1 cell thick and consists of narrow epithelial cells, with finely 

 granular or fibrillar cytoplasma ; often the cells are broader in which case they are transparent. 

 A spiculum originates from 1 cell, which afterwards surrounds it as a little cap. The spicula 

 remain in connection with the hypódermis by thin threads, met with everywhere in the spicula. 

 Papillae are absent. In fig. 164 on either side (/>) a little knob appears, formed by a protraction 

 of the hypódermis and the muscles of the body-wall. By these knobs a superficial ventral furrow 

 is bordered. Here the cuticle is slightly thinner, whereas the hypódermis forms transparent or 

 extremely minute knobs, upon thin stalks (fig. 150). 



The cuticle is covered throughout with a thick layer of dirt, which hides the spicula 

 from view and causes the velvety appearance. 



A dorso-terminal sense-knot is present on the terminal extremity of the animal. 

 The ventral groove runs from behincl the mouth as far as a little way before the cloaca- 

 opening and has one large median fold and two smaller lateral ones. The " Flimmerhöhle" is 

 spacious and divided by a dorsal wall into a left and a right half (fig. 152): the wall carries 

 very long cilia. The "hinten- Bauchdriise" is very strongly cleveloped, especially around the 

 "Flimmerhöhle"; its granular, deeply staining glandular cells extend on either side of the pharynx ; 

 more distally the gland becomes less developed, though still discernible. Amongst its cells all 



