Cyathocormus mirabilis n. g., n. sp. \'J 



ing, the free edge of the lateral lips. On each side of the 

 base there is a zone of large columnar cells without cilia which 

 stain only faintly and seem to be glandular in nature. Beyond 

 this glandular zone the cells are again ciliated, but the cilia 

 are very short, and the cells bearing them become successively 

 shorter as they are traced away from the base. On the inner 

 surface of the lips there is again a zone of ciliated epithelium 

 composed of cubical cells. The cilia are very short. On tracing 

 these zones anteriorly they are found to be continuous with the 

 band of ciliated epithelium covering the peripharyngeal ridge to 

 be described below. Seen from the dorsal or ventral aspect, 

 the endostyle shows a pair of thick semi-opaque bands separated 

 by a more translucent area (PI. I., fig. 6, end.). The opaque 

 bands are caused by the thickened sides, separated by the less 

 massive floor of the groove. The narrow dark lines seen along 

 both sides of the endostyle are the zones of ciliated epithelium 

 on the lateral lips of that organ. 



Dorsal lamina. The dorsal lamina is represented by a series 

 of three short triangular languets springing from the dorsal edge 

 of the branchial sac. Each languet is placed at the intersection 

 with a transverse vessel and is ciliated at the sides. They seem 

 to arise directly from the inner wall of the vessel, there being 

 no ridge or membrane present to unite their bases. 



Tentacles. The tentacles are placed in a circle round the base 

 of the branchial siphon just at the entrance of the branchial sac. 

 The branchial siphon is a short funnel with the rim turned out- 

 wards, and when wide open its diameter is about double its height. 

 Its inner surface is lined by an invagination of the superficial layer 

 of test, which is nearly of the same thickness as that layer and 

 extends as far doAvn as the tentacular circlet. 



The tentacles are simple and rather stout. When directed up- 

 Avards they project beyond the external opening of the branchial 

 siphon (PL IL, fig. 8, 10). They are generally sixteen in number 

 and are of three different sizes. Four are long and meet in the 

 centre of the branchial aperture even when the latter is wide open. 

 Four others alternating with these are somewhat shorter, while 



