44 



The Heterozooecia, which are spread among the zooecia singly or in groups, have 

 the same length as these, but the obliquely ascending distal end is provided with 

 a small elongate triangular aperture the length of which is contained four to five 

 times in the length of the whole heterozooecium. The fissure-like opening is bor- 

 dered by two inwards obliquely descending thickenings. 



Ooecia have not been found. 



Kenozooecia have not been found in the two small fragments examined. 



The Closure starts by the formation of a number of processes which rise from 

 the margin and grow together in a more or less irregular manner, thus forming 

 at a certain point of time a calcareous cover perforated by 3 — 5 hollows which 

 later get closed. 



The Regeneration. I have seen a few cases of regeneration both of zooecia and 

 of heterozooecia. 



I have examined two small laminar fragments one of which has only the lo- 

 cality France while the other which I have bought from Mr. W. Gamble is from 

 St. Antoine du Rocher. Under the name of Semielea plana Mons. Filiozat has 

 sent me three small fragments of another species which with the same right as 

 the present might be referred to Semielea plana d'Orb. The zooecium and the 

 aperture have the same form and structure, but the closure is effected bj' means 

 of a concave lamina, and in one of them I have found a heterozooecium a little 

 longer than the zooecia and the aperture of which has about the same form as in 

 that figured in pi. II, fig. 9. 



Meliceritites cenomana d'Orbigny. 



Nodclea cenomana d'Orbigny, Bryoz. Crét. p. 609, pi. 761, figs. 11 — 13. 

 I PI. Ill, figs. 17, 18.) 



The Zooecia, which are not twice as long as broad, are rhombic or hexagonally 

 rhombic and divided from each other by the well-developed peristomial thickenings 

 together with the tubercles which are as a rule well-developed and sometimes very 

 large. The half-elliptical or triangularly rounded aperture, which together with the 

 peristome takes up the whole breadth of the zooecium in its distal part, is half a 

 time longer than broad, much longer than the suboral area, and the supra-zooecial 

 tubercle forms a more or less developed, sometimes very robust beak-shaped pro- 

 jection. No distinct oral ledge. The convex operculum is provided with a flabelli- 

 form striation. * 



The Heterozooecia which seem to be very rare are much larger than the zooecia 

 and provided with a very large tjuadrangularly rounded aperture which is about 

 twice as long as the suboral area. No lateral thickenings. 



Ooecia have not been found. 



No Kenozooecia. 



