R. M.Bnjdone — Fartlier Note^ on the Trimming ham Chalk. 295 



slender and projects over tlie adjacent cell (n). The point being 

 raised much higher than tlie rounded end, the aperture is in an 

 inclined plane facing the cell adjacent to tlie base of the avicularium. 

 It is an almost invariable rule that every cell (except the very early 

 ones) has either an ovicell or an avicularium. The species is very 

 characteristic of the Triinmingham Chalk, but is recognisable in the 

 zone of M. cor-anguinnm, though rare below the zone of B. miicronaia. 



Semikschara Mundesleiensis, sp. nov. (Fig. 4.) 



Colony always adherent. Cell large and subpyriform, with the 

 external area of the pyriform type occupying usually about one-third 

 of the cell, but only tapering very slightly as a rule. Where the 

 marginal wall divides the internal and external area it is very faint. 

 The aperture is veiy large and occupies nearly the whole of the 

 space within the marginal wall, and is slightly heart-shaped, its 

 low^er margin being indented by a blunt denticle projecting from the 

 internal area. The internal area is usually very insignificant, but is 



Fig. 4. 



very variable in extent, and may absorb almost the whole external 

 area. It slopes forwards and downwards. The ovicells are not at 

 all prominent, and are little more than swellings of the foot of the 

 succeeding cell, but have a very remarkable thickened broad rim to 

 the aperture. Avicularia rare and very irregular in occurrence. 

 They are narrow elongated membraniporine cells, with a slight area 

 at the foot sloping gently towards the aperture, which is slightly 

 constricted rather above the middle. The size of the aperture makes 

 the species easily recognisable. 



Sbmieschara Canui,^ sp. nov. (Fig. 5.) 



Colony always free, but unilamellate. Cells relatively broad, 

 aperture placed in the upper third, small, trifoliate, upper lobe serai- 



Fig. 5. 

 circular, other lobes narrow and exactly alike. No ovicell observed. 

 Avicularium an elongated cell, slightly constricted rather above the 



^ Xaiued iu honour of my friend M, F. Cnnu, the French authority on Polyzoa. 



